Yes it can be done this way. However we will end up having the same pack definitions in the product specific install.xml as well as JEMS installer's install.xml. Short term this is ok. We will just need to be careful to keep all the install.xml files in sync.

Long term we need to avoid this. When installers are assembled from the components which represent file packs, we should have no problem with keeping install.xml files in sync since these files would be generated during the build time.