granting permissions before joining server ?

Some permissions plugins foolishly don't grant permissions until after a player has joined the server.
or at least from my recent experience anyway with PermissionsEX

as i would like my donators and staff to have essentials.joinfullserver or whichever plugin i decide to use
so which permissions plugin gives players their permissions before joining ?

i think groupmanager does this but i have never used it before can someone verify ?
and would it be hard converting from PEX to groupmanager/whichever plugin you recommend ?

needed for mc v1.6.4

thank you in advance