Switch between multiple "persona" accounts?

Hi, I own a roleplaying forum http://hogwartsahistory.forumotion.com/ and I was wondering how to link different "persona" accounts on to one main account.
The main account would be for general out-of-character chatter, and the linked "persona" accounts would be the player's characters.
A site that does this is http://thebbaforum.com/

In short, is there a way for members to create additional accounts off of their main one and switch between them freely without having to log-in?

I don't quite understand what you are asking but from what I understand you want users to have multiple accounts and to be able to switch between them without having to log out and log back in.

If so then no you cannot do this, not that I am aware of anyways.