How can I group rooms together with GH?

I just got the smart things hub and have all my lights and switches linked. I want to group items together like upstairs and downstairs and even further group them by assoication like Kids room(all kids bedrooms and play rooms), entertainment rooms(movie, family) and have the rooms controlled either as half the house(upstairs, downstairs) or by their groups.

When I put items to a group in the smart things app it removes that item out of the previous group. Is there not a way to do what I want and have it work with Google home?

Maybe they can help you in the other thread, but natively, linked devices can only be placed into one room.