Show values from first table when slicing a second related table

I have two tables which have a many (table 2) to one (table 1) relationship. I have a slicer applied to the second table. When the number of rows in table 2 related to a row in table 1 drops to 0 (due to the slicer), the row in table 1 will now no longer show up in any visualisation in that page.

How can I show a list of values in table 1 that have been filtered out due to the filter applied on table 2? My example here is to show a list of sites (table 1) for which there have been no inspections (table 2) in a particular time period (slicer).

Cheers