Create a Lotus Domino Groups like: „ironport.mail-smtp-relay.lookup1“ for later use create also „ironport.mail-smtp-relay.lookup2“ … (Lotus Notes Text field limit!)
Settings Ironport LDAP Server Profile:
Example: Allowance Query String
(&(objectclass=dominoGroup)(cn=ironport.mail-smtp-relay.lookup*)(member=*{a}))