Okay, here's how I'd do it step by step:
1. Create two new Phantoms. Name one "BOB'S CELL", name the other "FWD CONTROL"
2. Create two new SYS FWD paths. Name one "XYZ HUNT", with the HG as sole fwd point, and one "BOB'S CELL", with the "BOB'S CELL" phantom as sole fwd point.
3. Using feature code 359, then 355 (FWD ALL CALLS), fwd BOB'S CELL phantom to outside (8? 92000?) and then the number. Place an IC call to this phantom to make sure it works.
4. Within the FWD CONTROL phantom add two new sys fwd paths. Top should be BOB'S CELL path, with DND only station flag turned on. Second should be XYZ HUNT with IMMEDIATE station flag only.
5. Redirect all calls currently going to XYZ HG to now ring FWD CONTROL phantom.
At this point the scenario will work. Call arrives and is directed to FWD CONTROL. If FWD CONTROL phantom is in DND, call goes to BOB'S CELL phantom. If not in DND call goes to next step, XYZ HUNT.
Icing on the cake: give users a PKM/DSS key representing FWD CONTROL, it will flash when FWD is ON. To place FWD CONTROL in DND, dial 359, DND CONTROL ext, DND control password (the one in the phone section, not the vmail one) and then 370#. To cancel, same procedure but use code 371 (no #). To make life better you can put these long strings under station speed dial buttons, I think they'll just fit within the 16 character limit; if not, use shorter ext number or pass code. Super trick: In db programming, under VIEW at the top, there's an ONLINE MONITOR choice that will allow you to type all those digits in under speed dials...but remember, at the set we call the first speed dial 1, but in db prog it's called 0...program the first manually at the phone, then use online monitor to view it, then type into other phones the same way.