I could suggest to add dn based membership. For instance:
dn: cn=news,ou=groups,dc=
example.com,dc=root,dc=dn
uniqueMemeber: uid=gfidente,ou=people,dc=
example.com,dc=root,dc=dn
mgrpAllowedBroadcaster: em...@foo.bar
Great tool mlapd!!
Regards
Marco