How to maintain private/secret/confidential branch.

Hi,

I don't know how to make such a scenario work:
- two repositories: pub, priv
- priv is clone/branch of pub
- there is some constant developement both in pub and priv
- there are regular syncs with pub in priv

Problem:
Occasionally I want to push some changes from priv to pub.
Then after syncing with pub I want to get as few conflicts as possible.

Is it possible to do with git?

Thanks
Lukasz