how to disable a collision pair ?

[Yann]

I'd like to disable some collision pairs in my bullet simulation.
I used to have constraints between some of my bodies, so it was easy to disable collisions between them. Now I would like to disable collision detection between these bodies, but with no constraints between them. Is there an easy way to do so ?

[Dr.Shepherd]

collision masks, check the tutorials...

[Yann]

thx, dunno how I could have missed it

[Dr.Shepherd]

It's all right...Actually, I think though the tutorials are always blamed for their simplicity, they did cover the most essential information