I’ve never seen that Club checkin would refuse to checkin some part of a group of people presenting themself at the same time even on multiple bookings. The only problem I would highlight that which reservation gets the bag assigned. This is not an issue until the bag goes missing. Then its a downhill to explain who’s bag under which reservation, etc. Sometimes checkin agents just assign all bags to the first PNR they see, so you get assigned with your friends bag or the other way around. Officially the person name on the bag receipt has the ability to deal with any issues. Other than this I dont think you will have any issue with checkin.