Width Rule for BGA packages

Hello

I am abit confused about the use of rooms and classes in altium. Actually my problem is i want to define width rule for my two BGA packages so that they can be routed at different widths than all the board. What should be my query statement. I have tried ''IsBGA'' command but it is not working for me. Any other ideas.?

Define a room in the required layer and define a rule saying within room 'specify room name' and define width rules