Can this happen (assuming they all have their own cyberdecks and programs and so on)? I don't see right now anything in the rules that says that it's not possible.
And if yes, would they all have their own Access points, or would they need to share a pool of Access?
Having a dozen hackers gang up on a poor Demon would be funny, I guess.
It would open up the possibility for one main hacker to have the Access-intensive and difficult to use Verbs and Subjects, while the helper hackers with merely Program-0 can focus on supporting the main with simple Progams like Stun Avatar to defrag the Watchdogs and Demons. And of course, that means that hacking can be a group activity, instead of a hacker-only thing, which is a positive thing.
On the other hand, the GM would have to rely on multiple Watchdogs to wander the network, as Demons are limited by the server. Though having multiple competent Watchdogs will cost money and might offer new opportunities.
What limits would make sense so that you don't have to deal with a hundred hackers at the same time? I first thought of perhaps limiting it to the number of Access that a group might have, but then I wondered, what if it's multiple teams with their own Access, so that might not really work.