[xmlblaster] Message Structure ..

[Arghad Arnaout <arghad at gmail.com>]

Hallo Everybody:
OK .. I have a question related to the message structure in XMLBlaster:
What if We want to create a topic which accepts only well defined messages structure,
for example, what if I want to create a topic accepts the messages in the following format:
<book>
<title>Title of the book</title>
<ISBN>08324937424324</ISBN>
<publisher>Publisher here .. </publisher>
<pubYear>2006</pubYear>
<cover>image of the cover</cover>
</book>

I searched the requirements and examples for such thing and I found that we need define filter plug in to do that .. 
Am I right ???? or we can do that using a different way .. 

Thank you .. .
ARGHAD