2 pump ststem?

hi i have system with 2 pumps 1 for h/w the other for heating but the system has no stats -im thinking of fitting room stat and cylinder stat and running them in line to switch the pumps -is there a way i can switch the boiler at the moment its switched on by the hot water side of the timer so the heating side will only run if the h/w side is on aswell -being an oil boiler its working out very expensive to run-any ideas ?