How does multiple active service accounts work?

[Quesse]

I recently bought the CE of 1.0 and plan to buy the ps3 of ARR... So eventually I'll have 3 active service account at once... Now how does it work in-game? From what could see, we could have 8 players per service account so if I have 8 players on all of my service accounts do I have to select which service account I want to use every time I log in or are all my characters listed at the time? I doubt the latter since there really only (currently) have 8 available slots... Maybe there is a tab on character select to navigate between service accounts...

There's no way to associate service accounts with each other (that seems to be what you're asking). In other words your 3 accounts are separated just like they are with anyone else's account - with a Username/Password and/or security token.

You can login with any account on any PC or any PS3, which answers your question, yes you have to select (via username) which account you want to use everytime you launch the game.