I can't find any function stating "disable". Only an edit, which appears to only allow the change of name; and an X which I presume removes it. Is that what you mean?
I don't have any other numbers, I could just ask friends to call me.
So as I understand it, once I remove my cell number, and a friend calls me, we want to see if my home phone rings? I'd have to do that a lot, as I do receive calls where my home phone rings, it's sporadic when it doesn't.
But my cell never rings.