Yes JP and a number of posts are on the fora to describe it, one in an exchange with I think MovieMan. Just install a second client to it's own folder e.g. BOINC2Sneaker. Do this when the regular BOINC is exited, get work, set the activity for network to OFF, exit the second install, copy to jump drive, copy to second pc in identical directory structure.... i.e. it should be called BOINC2Sneaker on the internet-less machine, run till finished etc.

Housekeeping needs to be done meticulously else the servers get confused who's who and work being declared as not belonging to one or the other client. OS and CPU must be similar.... try if it flies.

It's not a regular set up, and not recommended for the compunoid.