How hard would it be to code a calling for help mechanic? (For a custom OM)

[GoblinGuard]

In various pokemon games, pokemon have a mechanic where they "call for help". How hard would this be to integrate into pokemon showdown?

I'd want a clickable button like Dynamax or Z. Then it would check for whether the pokemon is holding a specific item - and depending on the item, a different pokemon or a different group of pokemon would show up to help, only to disappear when fainted or after a few turns.

This requires essentially turning a single battle into a double battle temporarily - is this doable or complete bogus?

 

[pulsar512b]

this sounds quite difficult to implement for basically no gain tbh but idk