I am looking for a very specific feature/plugin for LDAP lookup.

If I understand correctly OTRS is using something like https://metacpan.org/pod/distribution/perl-ldap/lib/Net/LDAP.pod for the LDAP auth ? 

Which seems to have the ability to meet my requirements.

What I would like to do, is an ldap search to query the members of a Group. (Much like it already does for Customer or Agent auth.)

I would like to list those members in a ticket, somehow and send them out as a notification.

Would someone be able to help guide in me the right direction to solve this?

Many thanks

Ant.