I'm using primefaces in an app that is currently in version 5.2, but I needed a component that is only available in version 6.0 > = for another project. I use the two designs in the same glassfish installation. When I rounded one of the projects, it gave incompatibility of the primefaces that were in the glassfish (half obvious).
Well, a solution (for local use) that I attended was to have two instances of glassfish (see installation) where on a squeeze with primefaces 5.2 and in the other 6.0, but in production environment, would have to use a single installation of glassfish and for each project use a different set of libs? Like in that case of glassfish versions.