Validation Type Dependant on Validated List.

I'm using excel as a script builder for an automated system. We have power supplies and relays. In Column B I have a list of possible Actions. In Column C I have paramaters for that action.


IE:

Column 1                  Column 2
Power Supply 1 (Volts)   10 <~ Setting PS1 to 10V
PS1 Frequency (Hz)       100
Relay 1                  Close <~ Closing Relay

Right now, I have Power Supply Voltage being a list 0...10 (VIA Dependant Validated Lists.) But now I want to allow Decimals. However, for the Relays I only want Open/Close.

Therefore, the Relays would have a "List" Validation type, whereas the Power Supplies have a "Decimal" value type.

In addition, I want the range of the Voltage to be between 0 and 10, and the range of the frequency to be between 1 and 10,000.

How can this be done by using a custom validation type? Can it be done without VB?