Control+Click on Report Fixed List

Is it possible to perform a Control+Click on a Fixed List in OTM version 6.1.6? I have several fixed list items on my report parameters and the client wants to be able to select multiples, with 6 different items creating possible combinations will exceed the field width on the Fixed List values.  Since the items are not in OTM as specific items but as representative of classes of items I cannot use a finder and then use ONE OF.

For example, Fixed List values 1,2,3,4,5,6, and ALL. User wants to be able to use combinations of 1,2,3,4, 5, 6 and 1 may mean all items with xxxF1 and 2 alll items with xxx F2, etc.  I currently translate the passed value in the Report Request to use IF 1 THEN where item_gid='xxxF1', in my sql query etc.