That is a cool question. I don’t know the answer. I suspect it is possible, but a fair amount of work. A login session is represented by a cookie in the web browser, so you’d need some machinery to manipulate the cookie. This machinery is outside of what Auth0 currently does, so you’d need a web page to choose a session, that would swap cookies around. Along with the cookie swapping, you might have to keep track of access, id and refresh tokens.
I have worked with clients who solved this in a different way: they have a single account for each user, and the account has a list of personas that they are allowed to use. Then they switch from persona to persona. They log in once, to the account, and then have a selector for what persona they want to use. This isn’t what Google does, of course, but this is pretty straightforward to do, if it meets your goals.