Help with SELECTEDVALUE: How to exclude from my filter condition if more than one value selected?

PBI12345 Try this:

AsAt Leisure Revenue LY =
CALCULATE(
    SUM(
        'Data: RADAR'[Revenue Held (LY)]),
            ALL('Booking Agents'),
            'Data: RADAR'[Source] = "AsAt",
            'Booking Agents'[Psuedo Segment Type] = "Leisure",
            'Network Group Table'[Network Group] IN DISTINCT('Data: RADAR'[Network Group])
)