"The issue is that new released are sent out every 3 months"
Can't these other users simply run the software on their machines, and then download and install the updates as they become available? It's the simplest thing in the world to park an update package on a web-server and let people come in and download.
If you really don't want the software running on client machines you could run an application server,and let people login and work remotely, but it's an unnecessarily complicated way to go about it if you have lots of users.
You start off by saying you need to share the software with "many people", and go on to say that up to 5 people will be involved. I would let those 5 people run the software on their machines, and feed them updates via download.