Make a duplicate object unable to collide with itself?

In a game I am making I need an object which is spawned multiple times to be unable to collide with itself, but with everything else. Thought I could do this with collision masks/groups, but it works in the opposite way (collides only with itself).

How can I solve this?

Thanks

So can’t you put it in collision group 1 and make it only collide with collision group 2 for example? Seems to work for me?

I did that but it didn’t work at first. I fixed the problem by selecting no physics then setting it back to rigid body. Must have been glitched or something. Thanks.