[whpalmer4]

No, currently sync syncs everything in the active database. Your only choices that I know of are additional users, or putting the projects you want to hide in the Archive, which doesn't currently get synced. Both of those mean that you won't be able to see the "secret" actions in the same window as the regular stuff. If you've just got a couple of projects to hide, and don't mind checking two windows instead of one, this may not be a big issue. Just do File->Open Archive to open up the archive window, and use OmniFocus as you would normally.

You do have an OmniFocus family pack or a pair of licenses, right? My understanding of the license terms is that a single license would permit you to do what you are doing if you both use the same computer, but not if you use multiple computers. One user, multiple computers, or multiple users, one computer.