On Jboss5.x, you can achieve this by creating different directories under deploy folder.
For example: create two folders, "a" and "b"
put the war/ear/sar files in folder "a" which needs to be deployed first, the later folder "b" can be used for deploying war/ear/sar which needs to be deployed after the contents of folder "a" is deployed on Jboss.
JBoss lists the contents in alphabetical order of folders under "/deploy" and then proceeds with deployment.