Set a maximum (MAX) value for the computed total.

Hi All,

How would I set a maximum?

i.e people are adding up product prices, but the maximum purchase total at one time is $100 [combined total of say 3 items].
Should the value be more than 100 i guess options could be..:
* node doesn't publish.
* displays an error.
* node displays the maximum regardless (hoping they'd work out why it's capped after going back into it checking why their total didn't compute and re-reading the help text!).

Thanks in advance!!
p.s. I guess this could also help people looking to set a minimum
p.p.s. This is a fantastic module!