soldat only runs at the one resolution, and 3rd_account's suggestion is the only way of achieving what you want. With my
dual display setup, the resolution on the left display resizes to the soldat res. when i play soldat normally, but my right display stayed on with my messaging progs open.
i actually dont have it set up this way anymore, but you can configure the displays so that it only resizes one when you load soldat fullscreen.