Hide wp/admin/ for logged in users

Hello,

we have a problem. We created an online tool for a company. They have one subscriber login for all employees. They can login via a start page with out /wp-admin/. After they did that, the toolbar is not shown. But if someone knows only little about WP he/she can change the subscribers details. In our case someone activated the toolbar.

I tried WPS Hide Login but if the subscribers are logged in, the hiding of /wp-admin/ doesn’t work anymore. Only if they are logged out.

This of course makes sense, but has anyone an idea to solve this problem?

Thanks!
Dirk