Have anyone thought about a "Combined Summon"?

When two summoners have their avatar out, e.g. Ramuh and Garuda,

the two avatars are fused together into a more powerful avatar consist of two elements: Lightning and Wind, or say the element of "Fragmentation".

I would think this should cost both involved summoners a higher perpetuation cost in maintaining the avater.

Instead of doing another ridiculus quest for a new avatar that only summonable via Astral Flow, I think this would be more fun.