diff --git a/src/fiber_package/association.py b/src/fiber_package/association.py
new file mode 100644
index 0000000..1948d2b
--- /dev/null
+++ b/src/fiber_package/association.py
@@ -0,0 +1,11 @@
+from fiber_package.base import FiberBaseModel
+from fiber_package.refs import EntityRefList, CommitteeRefList, GuildRefList
+from enum import StrEnum
+
+
+class AssociationModel(FiberBaseModel):
+    full_name: str
+    # short name used for visibility strings (think: DLF, Kaiser, CNB, etc...)
+    tag: str 
+    
+
diff --git a/src/fiber_package/entity/enums.py b/src/fiber_package/entity/enums.py
index ba27d87..6d09ef5 100644
--- a/src/fiber_package/entity/enums.py
+++ b/src/fiber_package/entity/enums.py
@@ -2,8 +2,8 @@ from enum import StrEnum
 
 class Membership(StrEnum):
     member = "member"
+    activity_goer = "activity_goer"
     alumn = "alumn"
-    extern = "extern"
 
 class LanguageOption(StrEnum):
     nl = "NL"
@@ -12,16 +12,4 @@ class LanguageOption(StrEnum):
 class Gender(StrEnum):
     male = "m"
     female = "f"
-    nonbinary = "n"
-
-class HonoraryStatus(StrEnum):
-    merit = "merit"
-    honorary = "honorary"
-
-class OnlineAlmanacField(StrEnum):
-    address = "address"
-    birth_date = "birth_date"
-    email = "email"
-    phone_number = "phone_number"
-    study = "study"
-    gender = "gender"
+    nonbinary = "n"
\ No newline at end of file
diff --git a/src/fiber_package/entity/non_members.py b/src/fiber_package/entity/non_members.py
index d3a53ab..828515d 100644
--- a/src/fiber_package/entity/non_members.py
+++ b/src/fiber_package/entity/non_members.py
@@ -2,22 +2,10 @@
 from .person import PersonModel
 from .enums import HonoraryStatus, Gender
 
-class FormerMemberModel(PersonModel):
-    title: str | None = None
-    gender: Gender | None = None
-    honorary_status: HonoraryStatus | None = None
-    # TODO: picture, study_start (year, month?), study_end
-
-    # company emails?
-
-class AlumnModel(FormerMemberModel):
-    # membership: Literal[Membership.alumn] = Membership.alumn
-
+class AlumnModel(PersonModel):
     graduated: bool = False
     receive_spam_mail: bool = True
 
 class ExternalModel(PersonModel):
-    # membership: Literal[Membership.extern] = Membership.extern
     pass
-    # TODO... payment???
-    # TODO require login info??
+    
\ No newline at end of file
diff --git a/src/fiber_package/entity/person.py b/src/fiber_package/entity/person.py
index d8f4a2c..8c9d4b0 100644
--- a/src/fiber_package/entity/person.py
+++ b/src/fiber_package/entity/person.py
@@ -2,28 +2,29 @@ from pydantic import model_validator, EmailStr
 from typing import Self, Literal
 
 from fiber_package.base import FiberBaseModel
-from .enums import Membership, LanguageOption
+from fiber_package.membership_tag import MembershipTag
+from .enums import LanguageOption
 from .submodels import Address
 
 class PersonModel(FiberBaseModel):
     collection_name: Literal["entity"] = "entity"
 
-    membership: Membership
+    memberships: list[MembershipTag]
     first_name: str
-    tussenvoegsels: str | None = None  # only in Dutch names
+    infix_name: str | None = None  # tussenvoegsel in Dutch names
     last_name: str
     full_name: str | None = None  # first_name + tussenvoegsels + last_name
     email: EmailStr
     language: LanguageOption
 
-    # TODO: phone number
     address: Address | None = None
+    phone_number: str | None = None
 
     @model_validator(mode="after")
     def generate_full_name(self) -> Self:
         full_name = self.first_name
-        if self.tussenvoegsels:
-            full_name += " " + self.tussenvoegsels
+        if self.infix_name:
+            full_name += " " + self.infix_name
         full_name += " " + self.last_name
         self.full_name = full_name
         return self
diff --git a/src/fiber_package/membership_tag.py b/src/fiber_package/membership_tag.py
new file mode 100644
index 0000000..9c50af7
--- /dev/null
+++ b/src/fiber_package/membership_tag.py
@@ -0,0 +1,19 @@
+from typing import Annotated
+from pydantic import AfterValidator
+
+from entity.member import MembershipTag
+
+BARE_TAGS = ["public"]
+
+def validate_visibility_tag(v: str) -> str:
+    if v in BARE_TAGS:
+        return v
+    _, _, status = v.partition(":")
+    if status in MembershipType:
+        return v
+    raise ValueError(f"Invalid visibility tag: {v!r}")
+
+VisibilityTag = Annotated[str, AfterValidator(validate_visibility_tag)]
+
+def generate_tag(association_tag: str, membership_tag: MembershipTag):
+    return association_tag + ":" + membership_tag
\ No newline at end of file
diff --git a/src/fiber_package/refs.py b/src/fiber_package/refs.py
index 3088c69..a8e77ea 100644
--- a/src/fiber_package/refs.py
+++ b/src/fiber_package/refs.py
@@ -26,8 +26,9 @@ class RefList[C: str]:
     def __contains__(self, item: UUID7) -> bool:
         return item in self.uuids
 
-SystemRef = Ref[Literal["system"]]
-SystemRefList = RefList[Literal["system"]]
+
+AssociationRef = Ref[Literal["association"]]
+AssociationRefList = RefList[Literal["association"]]
 
 EntityRef = Ref[Literal["entity"]]
 EntityRefList = RefList[Literal["entity"]]
diff --git a/src/fiber_package/system/root.py b/src/fiber_package/root.py
similarity index 52%
rename from src/fiber_package/system/root.py
rename to src/fiber_package/root.py
index 7b8bd6c..0225004 100644
--- a/src/fiber_package/system/root.py
+++ b/src/fiber_package/root.py
@@ -1,6 +1,6 @@
 from fiber_package.base import FiberBaseModel
-from fiber_package.refs import SystemRefList, EntityRefList
+from fiber_package.refs import AssociationRefList, EntityRefList
 
 class RootGroupModel(FiberBaseModel):
-    associations: SystemRefList
+    associations: AssociationRefList
     sys_admins: EntityRefList
diff --git a/src/fiber_package/system/association.py b/src/fiber_package/system/association.py
deleted file mode 100644
index 857fcdf..0000000
--- a/src/fiber_package/system/association.py
+++ /dev/null
@@ -1,15 +0,0 @@
-from fiber_package.base import FiberBaseModel
-from fiber_package.refs import EntityRefList, CommitteeRefList, GuildRefList
-
-
-class AssociationModel(FiberBaseModel):
-    full_name: str
-    members: EntityRefList
-    committees: CommitteeRefList
-    guilds: GuildRefList
-
-
-    # TODO: also add former_members, alumns, etc... ?
-    # events: GroupList
-    # activities: GroupList
-    # mailings: GroupList