Can you clarify your question? Let me make some assumptions:
Role has a Resource Associated. Resource has an Entitlement linked, which points at an LDAP Group. (From memberUid I guess this an LDAP group).
So when you assign the Role to a User/Group/Container those who recieve the role, RRSD assigns the Resource as well. RRSD sees the Resource assignment and copies the entitlement value onto the user. This triggers the LDAP driver, which then does whatever it does with groups.
So can it be added automatically? Well if the LDAP driver does the work when it adds a user to a group, then yes. If not, no and you can modify the LDAP driver to do what you desire.