Is it possible to configure a VoIP account so that all calls from one specific number get forwarded to another (external) number?

Motivation:
Some company's fax machine tries to send me something about 10 times/week. I know the company, I've got the phone number of the technical guy responsible for the fax machine. Unfortunately it seems he is unable to solve it (or doesn't give it the necessary priority...).

So: I would like to forward all fax calls from their fax line to his number. Not very nice to do, but then again: they can stop it themselves, if they want to...

Is this possible, somehow?

(and yes, I know I can block a specific number - but that's masking the problem, not solving it)