Not possible with the Seam Resource Bundle (it's supposed to be a single big bundle - if you want multiple, then use traditional resource bundles).
Thank you Pete for your answer!
Concerning to store resourceBundles in to a database I have another question...
I want to store some labels in the database, which will change at most 2 times a year. This labels I want to make cachable, whit scope application if possible. Is this a good idea and do you have a hint for me how to implement it?
Yes, use application scope, and cache them e.g. in a Map. Caching read only data is easy :) You could even outject a Map into Application scope, and add properties to it. This should be very fast.