Hi @dpuccina
In case to set UID attribute based on group membership, please add the following lines in your schema of posixgroup type
<Schema aggregationType="group" displayAttribute="cn" featuresString="PROVISIONING" identityAttribute="dn" " nativeObjectType="posixGroup" objectType="posixgroup">
.....
<Attributes>
<Map>
<entry key="groupMemberAttribute" value="memberUid"/>
<entry key="memberAttribute">
<value>
<List>
<String>uid</String>
</List>
</value>
</entry>
</Map>
</Attributes>
<Schema>