The easiest way to do this is program it to RX with a PL tone nobody uses. A DCS tone usually works, although I'm not familiar with your particular situation. You have to make sure all the two-tone paging options are correct for this to work right. Let me know if you need more specifics.
On a side note, having used both, I personally prefer an actual pager over this option. In my experience, the Minitor II's outperform even the newer Minitor pagers.