Its one thing if they're on a limb its a whole different ballgame if they're inside a cavity in the tree, in the second instance it is unlikely you will be able to save this colony, yes you can save bees and add them to another hive through a combine but without the queen or brood for them to make another queen from their genetics are doomed.
You should contact someone that is very experienced with trapping bees out of trees in your area if you can find someone.
Good luck and best wishes.
...JP