My approach with my rather limited experience:
Settle in at a table or couch in the lobby. Keep an eye on the main entrance. When the big guy with muscle walks in, stand up, shake hands, greet him with a friendly smile, sit and chat a bit, then head up to the room. If you and he are halfways personable, it should all look perfectly natural.
Prolly a different story if you have co-workers traipsing back and forth in the same lobby, tho.