Siva,
A dynamic send port sounds like a good fit for your scenario. Here is a walkthrough for setting up a dynamic send port: http://www.codeproject.com/KB/biztalk/DynamicRouting.aspx. You need to look up the vendor info from the database, then go into a loop where you send the XML to each vendor. Since you are making multiple outbound connections, you might want to look at using an asynchronous pattern: http://www.codeproject.com/KB/biztalk/bts_async_call.aspx. The asynchronous pattern lets you open all off the outbound connections almost in parallell and then wait for the responses at once.
Hope this helps!