Can multiple personas on the same node use just one copy of the same program so long as it wasn't being used simultaneously?
For instance, can a team of hackers using a nexus use the same Exploit program so long as they aren't using at the same time? Obviously they'd all have to use separate Stealth programs to stay hidden.
Do they need to load a program into their persona to actually use it? Can the program just run on the nexus and count against it's processor limit while staying open for use by users on the nexus?

This is all just personal thoughts on the subject but I would allow any program on Nexi to be shared as long as parties involved had the proper access. That being said if one Persona had it loaded or running I wouldn't allow others to use it. Also it would seem to be easy enough to just keep one copy on the system and make copies for individual users.