As Brian said you can have 4 different extension, this could be 4 different DIDs or just 4 extension because you like to have a lot of extensions on your phone (maybe different locations). As long as those lines show up on a single phone, then you will be fine.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.