You can't reuse it directly as it would be working on a different association, so you would need to do some amount of rework (copy the form, change the association it is using, etc.)
One thought/idea/question - is there a reason you couldn't have a boolean attribute on the Door entity to indicate if a door is a the main door? This way you could have one association. You could build a microflow to run after commit on the door entity and set all other doors to false if the door that was just committed is true.