Active Directory memberOf LDAP syntax
Depending on how you're doing the adding, there are a couple of ways of doing this. MemberOf is a multi-valued attribute. If you're using an LDIF file, or direct LDAP syntax, you just add multiple MemberOf statements:
Department: Human Resources
MemberOf: CN=AAA,OU=BBB,DC=CCC,DC=DDD
MemberOf: CN=AAB,OU=BBB,DC=CCC,DC=DDD
MemberOf: CN=ABC,OU=CDE,DC=CCC,DC,DDD
Full Name: Milton Ives