You would need to create separate accounts for this purpose. However, you can link them all together so that you don't have to logout/login everytime you need to switch.
Follow this method after you've created all the accounts:
1. Log onto your primary YouTube account.
2. On the top right corner, click on your icon.
3. At the bottom of the pop-up that opens, click "Add Account"
4. Login to your other account.
That's it! Now if you click on your YouTube icon on the top right hand corner, you would be able to see your other accounts below your main account. If you click on the other account, it will directly take you to the second account without having to logout/login. This works vice-versa.
I hope this solves your query!