Lock dimensions

[wallywally]

 Very new here. Is there a way to prevent pre existing dimensions from changing when trying to only change one size? My first learning project is a simple 2 car garage. Once I built the exterior walls to the correct size, I am trying to add two garage doors on one wall with a walk door centered between them. I have plenty of room for everything on that wall. I want the garage doors to be a specific distance from the end of the wall on both sides. It is easy enough to put them all on the wall, but when I try to change any of the dimensions between items it automatically changes the opposite exterior walls size also. Is there a way to prevent this?

[wallywally]

Was able to do what I need with the transform tool