In your conf/jboss-service.xml, you can try substituting:
You would need to rename your deployment JARs 1A.jar and 2B.jar. The prefix deployment, deploys 1A.jar first because of the numerical precedence. It is assumed that you are talking about JARs deployed in the deploy directory.
There is more description about the scanner in the jboss-service.xml.
It may work for you. Some people have said that was not what they were after so I'm cautious about guaranteeing that it will solve your problem.