This might help you get started.
Sub CheckForPageBreaks()
Dim i As Integer
For i = 1 to ActiveSheet.UsedRange.Rows.Count
If Rows(i).PageBreak = xlManual then
MsgBox "There is a manual page break above row " & i
ElseIf Rows(i).PageBreak = xlAutomatic Then
MsgBox "There is an automatic page break above row " & i
End If
Next
End Sub
Change the code to insert a green line as required instead of create a msgbox. Can't program it at the moment, as I'm at work... But this should be somewhat helpful to start you off.