Okay, I did this, and it works well if I'm only selecting one range, but I want the parameter to allow for multiple selections.
My formula looks like this:
({?Range Select}="< 101" and Sum ({HORDHDR.ORDERTOTAL},{HORDHDR.CUSTNO}) >100.99)
or
({?Range Select}="101-1000" and Sum ({HORDHDR.ORDERTOTAL},{HORDHDR.CUSTNO}) <> 101 to 1000.99)
or
({?Range Select}="1001-2500" and Sum ({HORDHDR.ORDERTOTAL},{HORDHDR.CUSTNO}) <> 1001 to 2500.99)
etc.
So the formula is saying: suppress this section when the parameter chosen is "< 101," and the totals come to more than 101, so all the totals I want are shown. But when I select more than one range, they cancel one another out and no values are shown. How can I fix this?