It would be helpful if Axiom offered the ability to filter a screen that has been assigned to an asset category (using the same method used for the asset templates and grids).  For instance, contains([%asset%],'LOUISVILLE') or contains([%asset%],'LEXINGTON') typed in the "Search" bar for the page would only allow assets located at Louisville or Lexington to be shown or clicked on.  Similarly, if you were only interested in the ability to chose units that were operating, you could use something like [STAT_OPER]=TRUE as the filter.