Slicer - Single selection filters two values in table

andy_scott42  - If all you want is the list, you could add a column "mapping" and duplicate the rows for the "Both" rooms. Create the following Calculated Table to see the pattern. You will filter on the "mapping" column and show the "Value" and "Gender" columns in the table.

aTest = 
UNION(
    ADDCOLUMNS(
        GENERATESERIES(1,10),
        "Gender", SWITCH(TRUE(),[Value]<4,"Both",[Value]<6,"Male","Female"),
        "Mapping", SWITCH(TRUE(),[Value]<4,"Male",[Value]<6,"Male","Female")
    ),
    ADDCOLUMNS(
        GENERATESERIES(1,3),
        "Gender", "Both",
        "Mapping", "Female"
    ),
    ADDCOLUMNS(
        GENERATESERIES(1,3),
        "Gender", "Both",
        "Mapping", "Both"
    )
)

Alternatively, you could create a disconnected parameter table, and add a Measure that will return blank if the required condition is not met. Here is the Parameters Calculated Table:

Parameters = 
 DATATABLE(
    "GenderParm", STRING, 
    {{"Both"},{"Female"},{"Male"}}
)

And here is the Measure. You can add this to your table visual and make the column width so narrow that it will be hidden.

Compare Lists = 
var a = values(Parameters[GenderParm])
var b = values(aTest[Gender])
var c = FILTER(CROSSJOIN(a,b), OR([GenderParm] = [Gender], [Gender] = "Both"))
return COUNTROWS(c)

Cheers!

Nathan