I got the iTune 10.0 + iPhone 4.0.2

I also have a win7, win xp which are from work, home.
ex.
I want only win7's mp3 to be copied
I want only winxp's movie to be copied

what i mean is i want the media files ONLY transfer to the phone and not transfering to another computer. (one way)
When i try to do so, itune said i can only access one Library.

Or can i do it like the one Windows mobile way with another software, i drag and copy the file i want to the phone?