I've never had any real problem getting up to 4 family guests into the lounges when I'm with them.

Even sometimes when I'm not even flying it works. Once there was a funny outcome... I checked 4 of my family into QF at LAX (I wasn't traveling), using the F check in, although they were in coach. The check in lady apologized profusely for not being able to admit them to the lounge (which is crappy to the extreme anyway) because it was way overcrowded, and gave us a $30 voucher for the food court outside - which the kids prefered anyway, cos it included the Golden Arches. Nice service!