You may benifit from explaining a little deeper what you are after. I expect your concern is more about the tiddlers they share, there are ways to encrypt individual tiddlers and without wanting to sound dismissive users can have there own tiddlywikis. The single file wiki by its nature may break some multiuser models unless the use is readonly. The folder or nodejs implementation could answer some multiuser needs.
There are a number of discussions that relate to this question that may boost multiuser use but the sharability and bundling or drag and drop of tiddlers can go along way.
Personaly I am Building a content distribution process to manage common tiddlers between many wikis including allowing specific tiddlers to be owned by specific wikis.
I have also raised the idea of a messaging subsystem to move tiddlers,,and there are those whos development skills are greater than mine also proposing similer ideas.
Give us a better idea of your needs.
Tony
Tduser,You may benifit from explaining a little deeper what you are after.
[...]
Tony