I'd suggest against setting up a method of manually importing updates to your WSUS server. In my experience (with pre 2.0 at least), there would almost always be complications and probability of getting your database corrupted (it might be better now with 3.0, but I highly doubt it). There's a way to copy updates to a disconnected WSUS, but I believe you can ONLY import from exported data of another WSUS server).
I think you should be asking the question of how much time you're going to spend in getting the actual updates (how would you filter which ones get installed, for which software?), and how practical this method of Windows updates is really going to be.
I suggest you talk it over with your fellow admin folks and come up with an strategy of getting the server updates to your WSUS as intended by Microsoft (make sure you allow ONLY what's needed before downloading updates)... if this is a 'bandwidth tightening' + security issue (depending on the kind of control you have over your bandwidth/access), you could just enable the ports and/or sites for WSUS, as documented here: http://technet.microsoft.com/en-us/library/bb693717.aspx
...or you could play with the solution provided by this link: http://www.wsusoffline.net/ (WSUS Offline Update). Looks like it was recently updated, so might still be relevant.