how to set priority of routers in ospf

Hello. I'm running ospf from a router against two other routers on the same ethernet segment. Those two routers a both capable of routing given prefixes, but I prefer one of them to do the actual routing and use the other one as a backup router in case of emergencies. How can I set such a preference? I thought of using ospf_metric2, but it is supposed to work only when ospf_metric1 isn't set, which is (checked using show route all). For some reason the configuration does what I need, but I can't figure out why. Could anyone shed some light on this? thanks mk