how do i make an object to not collide with a spesific one and the collide with all the others object (except the one i don’t want the object to collide with)
How about using collision groups? This may work just right for your case.
Can i create groups instead of associating it with one group ?
Yes, but there’s actually also a way to add actors to an actor’s Ignore Collision group. Should be a BP node that does this; you can do it dynamically at run time.
And how do i do that ? 
not sure what’s the name of the node.