No you can't trigger the hot deployment of the individual module in EAR by touching the deployment descriptor, why would you need to do so?
I guess you would like to save time in deployment, the entire EAR would be taking much time to redeploy, am I right?
You may play with the corresponding MBeans, it may allow you to deploy/undeploy individual ejb's.
You could also have take the ejb deployment artifact out of the EAR and keep them use the same classloading, this can be achieved by scoping the EAR and seperate EJB deployments.
Can you explain the scoping the EAR and seperate EJB deployments?
Should I deploy the EJB jars as seperate parts, then how will they find each others classes and jars?