Dimensions/distances

[96Mustang460cid]

I am trying to put multiple windows in the garage. I will set a distance from one window to a reference point (wall). Then, the next window is referenced off the first window. When I change the distance between the two windows, it pushes the first window (which I already dimensioned) back. One step forward, one step back ---> lather, rinse, repeat...

I want to dimension one window and put a 'hold' or 'fix object' on it, but don't see that option. Suggestions?

Have a good day!
Michael