Second user account can only log into first user account's Google ID

[Elliot B.]

I have a tablet with Android 5.0.1.

 

I am the main User.

 

I have set up a Restricted User account (Settings > Users).

 

When I log into this account and open, for example, Google Play Books, it's showing all the books associated with the main User's Google ID.

 

This is a security issue.

 

I want the second account to be able to a separate Google ID associated with it.

 

From within this Restricted account, when I go to Settings > Accounts, I see no way to add a second Google ID specifically for this second user.

 

Any ideas?