Full control over players in multiplayer

I’m about to create a series of game concepts in multiplayer that’s going to be 1v1 - 2v2.
but I wan’t to gain full control over player one and player two.

player one should be able to, say for the sake of the argument, change player two’s walking speed, so that player two cannot walk faster than player one.
this is not the concept, but pretty much explains how I want to interact between two players in multiplayer.

sorry for the vague description!