You can request multiple licenses for the RPL Hybrid package in your billing account. Once it is approved, you will need to download the package again. In the package file name you will see all domains listed. This package will work fine on all those domains. If you already have a working RPL Hybrid package, you need to install the downloaded package to a new Joomla and then copy all RPL Hybrid files from /components/com_rpl and /administrator/components/com_rpl to your existing RPL Hybrid installation.