How to give mating in a ball bearing.

You shouldn't really waste time mating a bearing.

But if you really want to:

In part studio create a mate connector to center of inside or outside race, then set it's parent to one of the ball bearings.

Fix: outside race
Revolute: inside race + outside race
Group: All Ball bearings
Revolute: Ball bearing mate connector + inside race

Now if you like realism with the above setup:
Use gear relations between ball bearing mates

...

But seriously, just use 1 group mate on everything. Or do a boolean union in a part studio for bearings