You only have one user that has access to create databases, but do you have the power to create new users that do not have DBO type powers?
If so, create one for each database and make sure they only have read/write access to their database.
If not, then I don't think so.
Can I ask why it matters anyways? It's not like people at your site are going to know the login being used to access the database. What is the requirement behind making sure a user connected to DB1 can't change things on DB2?
Users typically aren't the security risk.....it's the people behind the users. In your world, you're the person behind any/all logins on those databases so as long as you can trust yourself......I think you'll be fine
