Business check-in is for the status passenger and others on their booking, though I think in practice if you all turn up at the desk together it would only be the jobsworthiest of staff members who would send the unentitled passengers away to whY checkin.

Assuming there are at least as many silver as non-silver passengers, there will not of course be any difficulty at the lounge. For convenience of the lounge dragons, present yourselves in the order of silver-blue-silver-blue as that's the order the system wants to see the boarding passes.