Make Mjolnir like the Venom Symbiote

Most player have probably noticed that Eddie Brock and the Venom symbiote are different entities in the game. If you never did, try pairing 4* Venom (Eddie Brock) and 4* Venom (Agent Venom). You can't, because they are both Venom, right? Then try pairing 4* Venom (Eddie Brock) and Anti-Venom. You can't do that either, because they are both Eddie Brock. But you can pair Anti-Venom with 1* Venom, because 1* Venom is Mac Gargan, aka Scorpion. And obviously you can't use 1* Venom and Scorpion together because they are both the same human, one hosting the symbiote and on not.

I think there should be a similar restriction affecting Mjolnir. You should be able to use 3* Thor, Captain America (Worthy) and either versions of Thor Jane foster as they are all wielding the same hammer. Maybe the same restriction should be applied to Captain America's shield, though currently it would only apply to the many Captain Americas and 4* Sam Wilson (since Peggy Carter is, theoretically, from a different universe).

Is the Spirit of Vengeance possessing 5* Deadpool the same that possessed Ghost Rider (Jhonny Blaze)?

The Phoeninx Force has been divided between the X-Men to form the Phoenix 5, so I guess it's ok if 5* Emma, Colossus and Cyclops can be used with 5* Jean Grey.