In Virginia Beach, the radio IDs are set up like 558XXXX, the number after 558 usually indicates which department the radio belongs to and if it's a portable or mobile. For example:
VBPD Mobiles: 5583XXX, 5584XXX
VBPD Portables: 5580XXX, 5581XXX
VBFD Mobiles: 5585XXX
VBFD Portables: 5584XXX
VBEMS Mobiles: 5587XXX
VBEMS Portables: 5586XXX
Logging unit IDs for VBPD is no fun. They're always changing radios around so there's really no point. VBFD on the other hand is worth getting the unit IDs. I've been working on a spreadsheet for the IDs since about July and have gotten a decent amount
logged. They're not all entirely accurate but it's something.