non-parameter validation

[eluser][email protected][/eluser]
Hello,

I tend to use the Validation for all of my form-validation and it works beautifully. However, how can I execute a custom method that is not related to a single parameter, yet still using the class?

ie.

i have a method called

function validateAlgorithmAmount($x, $y, $z){}

where $x, $y and $z are three different post parameters.

how can i call this function, and then on the front-end display when it fails???


thank you.