You could do something with APIs.
Private Const SW_SHOW = 5
Private Const GW_HWNDNEXT = 2
Private Declare Function FindWindow Lib "user32" Alias "FindWindowA" _
(ByVal lpClassName As String, ByVal lpWindowName As String) As Long
Private Declare Function ShowWindow Lib "user32" _
(ByVal hWnd As Long, ByVal nCmdShow As Long) As Long
Private Declare Function GetWindow Lib "user32" _
(ByVal hWnd As Long, ByVal wCmd As Long) As Long
Private Declare Function GetClassName Lib "user32" Alias "GetClassNameA" _
(ByVal hWnd As Long, ByVal lpClassName As String, ByVal nMaxCount As Long) As Long
Private Declare Function GetWindowText Lib "user32" Alias "GetWindowTextA" _
(ByVal hWnd As Long, ByVal lpString As String, ByVal cch As Long) As Long
Function FindWindowPartialX(ByVal Title As String) As Long
Dim hWndThis As Long
hWndThis = FindWindow(vbNullString, vbNullString)
While hWndThis
Dim sTitle As String, sClass As String
sTitle = Space$(255)
sTitle = Left$(sTitle, GetWindowText(hWndThis, sTitle, Len(sTitle)))
sClass = Space$(255)
sClass = Left$(sClass, GetClassName(hWndThis, sClass, Len(sClass)))
If InStr(sTitle, Title) > 0 Then
FindWindowPartialX = hWndThis
Exit Function
End If
hWndThis = GetWindow(hWndThis, GW_HWNDNEXT)
Wend
End Function
Sub CopySheet()
Dim objXL As Excel.Application
' A suitable portion of the window title such as file name '
WinHandle = FindWindowPartialX("LTD.xls")
ShowWindow WinHandle, SW_SHOW
Set objXL = GetObject(, "Excel.Application")
objXL.Worksheets("Source").Activate
objXL.ActiveSheet.UsedRange.Copy
Application.ActiveSheet.Paste
End Sub