this is for the first and second combo boxes only.. do the similar coding for the rest of the combo boxes
Private Sub Combo1_AfterUpdate()
Dim strVal As String, j, x
j = Mid(Me.Combo1, InStr(Me.Combo1, "-") + 1)
For x = j + 1 To 16
strVal = strVal + Chr(34) & j & "-" & x & Chr(34) & ";"
Next
Me.Combo2.RowSourceType = "value list"
Me.Combo2.RowSource = strVal
End Sub