12 cans are not very big. Why not just add all the banks to the class path?
Alternatively, you can create another jar and specify all the banks in the Class-Path variable in this MANIFEST.MF jar, and then add this single jar to your classpath.
EDIT:
This is how I do it. Create a MANIFEST.MF file with content similar to this:
Manifest-Version: 1.0
Archiver-Version: whatever
Created-By: whatever
Built-By: author-name
Build-Jdk: 1.6.0_34
Class-Path: jar1.jar jar2.jar jar3.jar
replace jar1.jarthe actual jar file names.
: jar cvf test.jar -m ./MANIFEST.MF.
, classpath, java -jar xyz.jar class-name