have you tried doing 10.9.0.0/22 or 10.0.0.0/21First of all what protocol are you using? ospf or a eigrp or rip or..... since you have to figureout which one is DR/Main-routerin ospf you could just net 10.9.0.0/21if eigrp then you can use summary com...

I belive you have to use a If a network you use x.x.x.0 255.255.255.0(or else)if a single host you have to use x.x.x.1 255.255.255.255