separation for multiple users for the virtual world

We are going to develop educational/medical simulation. In our application, each user (student) should "get" the same instance of the simulation. But they should not be able to "visit/ work on" each other simulation.(I.e. the same avatar "works" in the laboratory for each student, but each student has his own laboratory/avatar instance and he can`t see what others do) As well users around the web should not be able to "enter" the simulation/s.
What should be a correct approach/design for such application? I probably can make several regions / running the same code ...Not sure that it is correct approach and how provide them a privacy (own instance of the world) ...
Additional question is there an option not to use (known client) viewer, but web / client application?
Thanks

It's possible to create multiple parcels in a region and set each one such that people outside that parcel can't see anyone inside (although they can see that actual items in there) so that may be one solution. You can set the permissions such that only particular avatars can enter a parcel so you could create one area per user and set each one.

If it's a complex setup instead you could set up small regions and use the OAR backup file to create many regions as copies.

In terms of viewers, there isn't really any way to use a web browser that I'm aware of.

In terms of access, you have to specifically set up hypergrid access, so not doing so will limit access to only those you wish to use it.