What version are you running on? Do you have the ability to do cross data source filtering (requires version 10+)? This would require that each source have a [Region] and [Hospital] column.
Best case scenario - the fields are all named the same across all sources. If so, great and everything will work by selecting the highlighted option in the screenshot.
Not best case scenario but still doable - The fields are not named the same you will have to Edit Relationships manually for the other 79 sources to tell Tableau which fields match.
Another option is to look into combining all sources together through a union (requires version 9.3+) or using a data prep product a la Tableau Prep
Hope these options help