You'll need three backup jobs with two selection lists
Your current job (edit the selection list in text mode to remove the fourth server)
Your fourth server (two week working set)
Your fourth server full
That's what I was afraid of. Is there a way for one job to be triggered after another job is completed? This would be so I wouldn't have to "guess" when one job is finished so I can schedule the other job accrodingly.
Note: We are using DLT's.
You can use policies to kick off one job when another finishes. See the Admin Guide
or you could call a BEMCMD job that released the second as a POST job from the first, if you want to be really old school