Question

I’m using the subsites module to make a multi site system.

I’d like the users logins to the sites to be independent. So if a user has registered on one site, they can’t just go to another subsite and login – they have to register for that site too.

In other words – registrations on each subsite is completely independent.

Is this possible?

Answer 1

Technically it would be possible to write a DataObjectDecorator for the Member class, and add a SubsiteID to each member, and then add a filter for that SubsiteID with argumentSQL().
And you need to modify the register form to consider the SubsiteID and hook into the authenticator.
But could very well be that there are a couple of other points you need to hook into to get this to work.

So yes, it should be possible, but it is going to take a long time, and it will be a pain in the arse to get it working properly.

you should carefully consider if you really need it that bad that you need to go this way.
It should be possible to just work around this by using groups, and setting group permissions.