let garageIDwithFavVehicles = Vehicle.vehicles
    .filter( {favVehicleList.contains($0.model) } )
    .map { $0.garageID }
let garageOwners = Garage.localGarages
    .filter( {garageIDwithFavVehicles.contains($0.id) } )
    .map { $0.garageOwner }
// ["Cary's Garage", "Amy's Master Shop"]