API2 listforwards - question about parameters of the function

I have implemented some cPanel API commands in a script I am working on. When I call the function without the optional REGEX string, I get a complete listing of forwarders, as expected. I tried adding in a REGEX string to match an e-mail address, and it worked, but was matching against the value in the 'dest' field. Is there any way to run a REGEX match on the 'forward' field instead?