I'm not saying yes or no, as I am unfamiliar with telus' policy. I can, however, tell you that this is definitely not something that can be achieved through your device.
Posted from my CrackBerry at wapforums.crackberry.com
Try downloading handango to your pearl at handango.com. Once it's set up, go to software, tools, personalization and then choose BerryBlocker. This should do it. Hope it works.
Just make the ring tone for that particular number something that is so quiet that you don't hear it. Then you don't hear it and it goes to voice mail.