A family of Microsoft relational database management systems designed for ease of use.
Why are you using a key like that? A primary key has one and ONLY one purpose, to provide a unique identifier to a record. There is NO need for the PK to even be visible to a user.
You seem to have a need to sort the records in some way. The esiest way to do that is to use an Autonumber as the PK and Another field as a visible identifier.
If you can explain what this identifier is for, maybe we can help further