Layer collisions

Is it possible to disable/enable all collisions on a specific layer?

Yes: scirra.com/manual/28/layer

Also, check out the "is on layer" event.

I should mention Im using physics collision. I added all the objects with collision on layer 1 to a family, and when the player touches an object to disable the collision of that family. But family physics actions do not seem to be working. It was glitching out at first and I realised that it was because of two physics behaviours in the sprites, so I deleted the original ones to have just the family physics behaviour.

Durp... I didn't realise you had to set what object not to collide with, and I was just disabling collision with itself.

If you want to disable all collisions for a specific object type, you should be able to set collision to disabled without specifying which objects to stop colliding with. This doesn't work w/ asm.js-based collisions yet, but hopefully will soon.