Using multiple resource bundles

[Duggirala, Satyavati]

Hi
 
We use multiple resource bundles in our Application.
 
By default Struts gets the error messages used in validation.xml from
default resource bundle.
(ex: <arg0 key="prompt.username"/> prompt.username is obtained from
ApplicationResources.properties)
 
How can I make particular field validation error message to be obtained
from another resource bundle.
(I have prompt.username in a different bundle UsersResources.properties)
 
thanks
-Satya