OpenLDAP with referrals to other directory services

Hello All,

I have a requirement for a new infrastructure we are building.

Our organization has a AD holding all employees' account. I maintain a separate OpenLDAP server with other users' that are not employees. Both the groups (employees and non-employees) need access to a group of Linux/Windows/Solaris/Mac servers.

I want the employees to authenticate against AD and non-employees to authenticate against OpenLDAP server. Also all the Unix-related attributes for employees and all attributes for non-employees must come from OpenLDAP server.

I think this should be achievable by some combination of referral and the OpenLDAP directory design. I just can't seem to get the right idea, though. Any suggestions/pointers?

TIA, Prakash