Sort array of structs by a member of each

I am compiling data using the following structs:

struct Nursing {

var leftTime: Double
var rightTime: Double
var submissionTime: Date

}

struct Bottle {

var bottleQuantity: Double
var bottleUnits: String
var submissionTime: Date

}

struct Puree {

var pureeQuantity: Double
var pureeType: String
var pureeUnits: String
var submissionTime: Date

}

Then I create arrays of each type using data from elsewhere in the app.

var nursingArray = [Nursing]()
var bottleArray = [Bottle]()
var pureeArray = [Puree]()

I then filter each array for only entries that occurred in the last day.

let yesterday = Calendar.current.date(byAdding: .day, value: -1, to: Date())
    var todayBottleArray = bottleArray.filter( { ( $0.submissionTime > yesterday! ) } )
    var todayNursingArray = nursingArray.filter( { ( $0.submissionTime > yesterday! ) } )
    var todayPureeArray = pureeArray.filter( { ( $0.submissionTime > yesterday! ) } )

Finally they all get combined into a single unsorted array.

    var unsortedTodayArray: [Any] = []

    unsortedTodayArray.append(todayBottleArray)
    unsortedTodayArray.append(todayNursingArray)
    unsortedTodayArray.append(todayPureeArray)

Here's the question...while I know they're unrelated, the submissionTime property appears in all three. How can I sort unsortedTodayArray by submissionTime?