moving multisite to another domain

Reading so much I'm getting conflicted info. I"m currently hosting with godaddy on a shared server (anetwork.com). I use subdirectories for all my domains. I want to build a network using jgs.com as the base. I have multiple other domains (mostly WP) with sites that will be added and realize I have to use Domain Mapping. The key is, I have to keep the existing sites active so can I build (copy) Jgs.com on anetwork.com, add the other sites and then transfer the network back to jgs.com. Is this possible or do I have to start over? Do I need Jgs.com to be a dedicated IP?