Revit 2025 introduced "Sheet Collections". This concept is great - it allows users to group sheets together in the Project Browser. It is especially powerful when a user has multiple buildings in one file, because it allows the user to have multiple sheets with the same sheet number, for example (2) A-101 sheets, etc.
This is all great, but has one major flaw. The Sheet List schedule allows the addition of the "Sheet Collection" field. However, the field is not available in the Filter tab. This seems like an obvious place to leverage that field. This would allow the user to have a sheet index for each building in the file. Of course there are workarounds, like leveraging another field that matches the Sheet Collection field value, but requires additional work and coordination. I hope this is resolved in upcoming updates.