One feature I liked on Microsoft communicator is the ability to right clic one a group name and initiate a chat with all online buddies of this group.
I saw that pidgin is quite reluctant to allow protocol to modify the group menu.
But, looking at the purple-plugin-pack-2.7.0 (groupmsg one), I figured out how we can be able to do so.
I made a patch and it's working. With it, when user right clic a gourp, ther eis a new menu entry 'New group chat'.
I think memory management should be reviewed (I'm not sure every thing allocated are well freed).
When I close the group chat, another empty chat window is opened (I don't know why).
Except these 2 things it seems working.
I atached this patch, hoping you'll consider integrating this kind of feature.