I can't sync groups using either Desktop Manager or BES. (in fact, on BES, when I add or modify a group in the PAB, the BES server (according to entries the log.nsf on the server) doesn't even detect the change. But if I add or modify a contact record, BES does detect that.).
So it appears the answer may be no.
But, I can do a lookup of a group using GAL against the public Domino Directory, and that does work. But that is not what you are asking.
You can also create local groups on the BlackBerry. But that again, isn't what you are asking for.