No!

The two groups have conflict of interest, and obviously your group has an advantageous position -- otherwise the Easter euro guy wouldn't need to try to steal something from you.

Just do what your supervisor told you to do, and let him fight the combat -- you provide him with bullets and suppliers. You fine, you safe, don't worry about it.

BTW, make sure you keep everything surface-solid and neat, in a way that nobody can fault from you. For example, you make sure you look like a nice guy, you say Good morning to everybody, you say How are you to the Easter euro guy -- and for anything he tells you, you say: I see, huh, interesting, blah.....(then walk away from him, don't give too much time to him). If he is such an awkward guy, coming to your cube, you raise your voice like "You have a question?" (the actual meaning of this saying is: "Get out from here").