You can't really cross-link the PNRs. You can, though, throw yourself onto the mercy of any AA staff who are very likely to be sympathetic to a reasonable request not to separate you - if anything does go wrong with one reservation but not the other.

If you are in the airport and things go wrong (flight cancelled etc) you will be equally affected and AA will be equally responsible for all of you and you can ensure then that you are rebooked together by pro-actively requesting it. I assume you will travel to SFO airport together so you will be in the same boat there.

I think it very unlikely you will encounter something going bad with the children's flight that doesn't also go wrong with yours, and then you can handle it for the whole party. So booking the children on separate tickets should be low risk.