Handling/Parsing/Validating multiple XML Statements

I am on the server end of a client-server setup.  I am using a Xerces-C++
parser with XML Schema validation.

The programmer working on the client end is sending me multiple XML
statements in one group.  The XercesDOMParser I am using does not like it.

I am looking for either a way to separate the incoming statements or
documentation to support my request that the client send only one at a
time.

Thanks.