We've experienced this with puppies who needed fewer walks than the older dogs, and also when we go to shows and have to leave some dogs behind. The way we've managed it is for one of us to stay with the dog(s) who is not going on the walk/to the show, and make a huge fuss of them, playing with them, generally making them feel very important and loved. After a time they grow to accept that not everyone will be going out at the same time - we still get the "You are sooooo cruel to me, where's the RSPCA number" looks, but two minutes after the ones going out have left, the ones not going out are fine.