I'm looking to invite 5 of my Steam friends for the mask, and potentially have new playing partners. Currently, I have 3 ready to go, the game installed but haven't booted, but only one of them actually show in the invite list.
I'll try sending invites via the Invite tab next to mail, not sure if that'll count though..
Hm, apparently there's another invite tab in the Friends list that shows all my friends.. I sent an invite to 1 friend via the dialog at the beginning of an arcade gate, and I sent the other 2 invites via the email method next to mail and news. Will they all work?