how to give someone access to homekit if they already are in a different family group

My wife has a family group that she manages our grandkids phones. I have started using HomeKit and have set up several accessories. Now I’m trying to add her so she can control the items in the house, but when she tries to except my invite it is telling her that she can only be in one family group.

Is that the only way to give her control to the HomeKit accessories or is there another way without her having to leave the grand babies family group.

Thank you for your help and any information that you can give