I have not found a possibility to exclude one database (I have two of them created in Pages) from sitemap. It seems like I can only include all records or exclude all records from all databases. Or I have overlooked a setting anywhere.

You haven't missed a setting, but I like this feature idea.

Still desperately needed.

We have some auxiliary databases that are only used for database relationship in other databases. The records in such databases do not make sense standalone. I would like to exclude those auxiliary databases from sitemap. They have a lot of records that do not really contain any helpful information on its own.