Users with multiple accounts

I feel a bit stupid because I googled so much I even triggered the google captcha to verify that I am not a bot. I might be using the wrong keywords, so if you just have a hint for me on what to search for I would already be eternally grateful.

I don’t have code yet, I’m in the planning/concept phase still.

I want to create a website where users can have pseudonyms - which are basically users but they are connected to one main user account. The main user should be able to switch between these pseudonyms without having to log in again.
Pseudonyms have the same views and functionalities as normal users. They have their own profile, their own picture, their own content, their own user ID etc.
They don’t need their own credentials otherwise. So no email address or password. You should not be able to log in as a pseudonym, you always log in as the main account.

If you want a more tangible example: If you know tumblr, I mean something like the side-blog system there. You have your main blog and then can have sub-blogs/sub-accounts. No one sees that a blog is a side-blog but you can manage your blogs only from your main blog and can switch to your side-blogs from there.

Any advice on how to do this? Honestly, just links to resources or some keywords or functions I should look into is sufficient. I am just stuck on googling for it because I don’t get the right results.

There’s nothing special or unusual about this.

I can think of a couple ways to handle this.

My first reaction would be to have a custom user object with multiple profiles.

The profile objects would have a foreign key to the custom user. However, what makes this slightly different is that I would add a foreign key to the custom user object referring back to the profile model.

The FKs from the profile model to the user model identify the set of profiles usable by the user. The FK from the user model to the profile model identifies the profile currently active.

Thank you so much! Profiles!!! yes of course
Classic case of ‘don’t start with stuff before you get the basics down’
I searched for identities, multi-accounts, roles (know a lot about the role system now so that’s a win), sub-accounts… but not for profiles.

Thank you! Now my brain is happy and I can continue to work through the basics.