The work around on the Cablevision thing is to setup in the online settings to forward busy to the main number on all the hunt lines.
I hear you but where I am I don't see that option. There's a problem too, there doesn't seem to be any consistancy from one region to the next with how they program their switches. Like with Centrex transfer- somebody says Cablevision provides it where they are, here it's 3-way calling.
-Hal