How do I install an outdoor wood burning boiler with my existing oil boiler?

What I specifically need to know is how do I keep the oil boiler's burner from firing when there is a call for heat. It will take a few seconds for the water in the oil boiler to get hot from the water circulating through the heat exhanger from the outdoor boiler. I was wondering if I could use a strap on aquastat on the incoming hot line from the outdoor boiler and connect it somehow to my oil boilers primary control box and then set the aquastat not to close unless the water temperature fell below a set temp.?