You shouldn't need to send money to PRS in the UK. It has links to partner organisations in other countries so you dont't have to go to that much trouble. In the USA I know the rules are slightly different but you have an organization called ASCAP that I believe is equivalent.

It should be like Leadfingers says - you pay a fixed fee to one organisation Actually in the UK there are three organisations involved in a recording:
PRS = Performing Right Society
PPL = Phonographic Performance Limited
MCPS = Mechanical Copyright Protection Society

But anyway you shouldn't have to contact all the individuals concerned, just the organization(s) that handle that business, pay a nominal fee and send them a list of what you've recorded and who wrote it. If you wrote any of the material yourself you could benefit by joining the appropriate organisation too. (that's the PRS here in the UK)

Anahata