A player character can become a 'being between worlds' (ergo a creature you can use summoning abilities on) via many different methods like the Chimera spell and so on.
My question is the following:
If a pair of summoners become 'beings between worlds' and both choose to make each other their respective familiars what would happen?
Would one be treated as "the summoner" and the other as "the familiar" or would they both be both at the same time? And if it is as in the first case what would happen if they made another ritual with inversed roles?