Possible to have custom message for a script variable's validation?

[k-masters]

Sorry if the title isn't clear; I was trying to keep it short.

We have a custom script with a variable that utilizes regex validation. Currently if validation fails it spits out the entire regex string in the error, which isn't really helpful to the end user. The example below accepts a comma separated list of email addresses. Ideally there'd be something a bit more human readable as the error message -- is that possible?

email = StringVar(
        label = 'Emails',
        description = 'Comma sepearated list of emails. Overrides default.',
        required = False,
        regex = "^([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25}(,[ ]{0,1}([a-zA-Z0-9_\-\.]+)@([a-zA-Z0-9_\-\.]+)\.([a-zA-Z]{2,5}){1,25})*$"
    )

I've also seen a similar error in a Custom Field that uses regex to match telephone numbers, but I'm not sure that case would be as easily addressable as a custom script would be.