Jumping DB's Easily?

I am setting up a Central Database to hold all the configurations of each
database. Each database will be idential in tables and stored procedures.
Question, when logging in, I want to be able to set datasource=#LoginDB#. Is
there a way to do this and use a different database on a person session
database. Example: { datasource variable } LoginDB = 'company1' { user
variable } User = '1' Datasource in Coldfusion = 'companies' with the default
database = 'company1' If another users logins and wants to use database
'company2' how can i switch to it for that user only and without having to
setup another datasource and setting for that user LoginDB = 'company2'
Thanks,