Gunnar

The rules allow you to check in at a Club desk and allow for you and one companion on the same flight into the business class lounge.

You should have no problems with all 3 of you checking in as I can't see any member of staff being that tight but you may find the lounge hit and miss. It all depends on if the lounge guard is feeling nice or not I am afraid. ( I managed to get considerably more than 2 friends into the F lounge at T1 the other week with some drunken banter with the lounge guard.)