Multiplayer in Vuforia: interaction between two markers/objects on two phones

hey guys,
is it possible to have interaction between various markers on one device?
following, is it possible to have a multiplayer solution on let's say two phones.
Example; two players having an object(car) each, both have the ability to drive one into the other.

Where would you begin? I have previously used Vuforia but how to go about including multiplayer and object interaction is tricking me out a bit..conceptually.

best,

 

Yeah, this is actual pretty hard I think. But I need it too! So good luck and let me know when it works