Your park and page buttons can match the normal park zones. Put a normal park801 on a 5410, and the rest can use park n page "8XX".

The only thing i will say is where you enter the P&P code, it will NOT error out if you interfere with the dial plan, but it does.

Also, the P&P feature puts teh park zone in the dial plan. So teh receptionist parks a call at 801, any phone can just dial 801. No need for a park button, just dial it like an extension...