Server wide auth for all Virtualhosts

I am trying to apply Apache auth for the Virtualhosts in my Linux server. The issue here is the Virtualhosts running under separate user inside the server and the document root is also different from each other. If I go to implement the auth, I need to edit each Virtualhost file inside the sites-enabled dir. This is a time-consuming task as there 300+ sites enabled in the server.

Is there any option/tool to implement this? I mean a server-wide single auth.

Thanks in advance.