I'm not sure I fully understand the question, but first thing that comes to mind is,
when going to the game layout, just loop through the peers using a for loop
+ System: For "" from 0 to Multiplayer.PeerCount-1
-> Text: Set text to Multiplayer.PeerIDAt(LoopIndex)
but instead of setting some text create your player sprite and setting the peerid variable with Multiplayer.PeerIDAt(LoopIndex)
but maybe I don't understand your question correctly