OpenDJ lets you look up which groups a user belongs to by using the
isMemberOf attribute.
$ ldapsearch --port 1389 --baseDN dc=example,dc=com uid=bjensen isMemberOf dn: uid=bjensen,ou=People,dc=example,dc=com isMemberOf: cn=My Static Group,ou=Groups,dc=example,dc=com isMemberOf: cn=Virtual Static,ou=Groups,dc=example,dc=com isMemberOf: cn=My Dynamic Group,ou=Groups,dc=example,dc=com
You must request isMemberOf explicitly.

