Password protection

Yes, you can use User Group Permissions feature.

Yes, you can use User Group Permissions feature.

I know about this feature. But we have multiple pages.
We have pages for customer, pages for inventory...
The user group permissions will only work for the customer parts but not with the inventory parts. Am I right

I think you are wrong.
the pharaon suggestion works for all pages on same project, but you have to check or uncheck the right option for the right user on the right side of user group permission definition.
Make some test first.
Tingo

Using User Group Permissions feature you can setup different permissions for all tables in your project.