Is your wire Romex cable? Is it in a conduit? If the romex wire is 12/3 w G then you mightbe able to make two circuts with a common, common. You must make sure the common wire is not over ampped with the two circuts under load. The common wire is also a current carrying wire when the circuts are in use, don't overload it.
If you ran a PVC conduit you could pull single wires (THW) and still use only one common (white) as long as it doesn't over amp.