vb.net validate end time combo box to display values after selected value of start time combo box

so I have a form (attached) and on it two combo boxes Start Time (cboAPCStart) and End Time (cboAPCEnd).

The code populates the combo boxes with time values (09.00am – 05.45pm) with 15 minute increments. There are 35 fifteen minute increments.

I want to validate the End Time combo box so that it only displays the fifteen minute increments that are after the Start Time the user has selected. So if they picked a start time of 10.00AM the End Time combo box will only have the values from 10.15AM. etc.

  Public Sub cboAPCStart_click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboAPCStart.Click

        Dim StartTime As DateTime = #9:00:00 AM#

        For i As Integer = 0 To 35
            cboAPCStart.Items.Add(StartTime.ToString("hh:mmtt"))
            StartTime = DateAdd(DateInterval.Minute, 15, StartTime)

        Next

    End Sub

    Public Sub cboAPCEnd_click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cboAPCEnd.Click

        Dim EndTime As DateTime = #9:00:00 AM#

        For i As Integer = 0 To 35

            cboAPCEnd.Items.Add(EndTime.ToString("hh:mmtt"))
            EndTime = DateAdd(DateInterval.Minute, 15, EndTime)

        Next

    End Sub