Apply a single validator to multiple controls?

[MattB]

Is there any way I could take a standard validator, like the
RequiredFieldValidator and make one validator check three text fields,
making it fire if any one is blank?
I know how I could do this with a CustomValidator and server-side code,
but my javascript is probably not good enough to write the client-side
from scratch and that's where I need this logic to work.
If not, does anyone have any good examples of the client side javascript
to do this with with a custom validator?
Thanks!

Matt