When you're working with BCBS clients, you should always file your claims to your local Blue Cross Blue Shield payer. Even when a client brings in a BCBS member id card from out of state, you should enter in their profile that their insurance company is your local BCBS payer so your claims get processed.
This means that you will only need to submit enrollments to your local BCBS payers. There is no need for you to enroll with any BCBS payers from out of state.
For example, let's say you're located in Hawaii and you have a client shows up with a BCBS insurance card from California. When you enter their insurance information you will need to ensure that the insurance company in their profile is BCBS of HI. Once you file the claims to BCBS of HI, the payer will route the claims internally to the correct branch to ensure that you get paid.
The same is true if you're trying to file claims to the Federal Employee Program (FEP). File your FEP claims to your local BCBS payer. This applies to every state with the exception of MI and CT. For those states you must use the payer IDs: MIFEP and C2BLS respectively.