Question regarding meta proxy server

Hello list, I set-up a meta proxy server (hopefully that term is correct), to combine information from an AD-server and an ldap-server. For some reasons (historical?) both are running and provide mostly different attributes. In principle it seems to work, as I get information from both defined systems - but I don't get all information as there're not the same attributes on AD and ldap. For example, the unique userID on AD is "cn" and "sAMAccountName", on ldap its "uid". So, when doing a: ldapsearch "(uid=USERID)" -H ldap://metaldapserver... I will get information from the defined ldap-server only, and when doing a ldapsearch "(cn=USERID)" -H ldap://metaldapserver... I will get information from the defined AD-server only. Is there still a way to combine both infomation? Debian Bullseye with Symas OpenLDAP Server, slapd 2.6.3 Cheers, Torsten