Referencing the active range of another workbook vba - vba

Question

Ok, so I am trying to perform a batch interpolation macro on some files in a folder and would like to know how I can refrence the ActiveRange from the .XLSM and feed it back into the for next loop for each selected file.
Sub Batch_Interpolate_Blanks()
Dim SaveDriveDir As String
Dim MyPath As String
Dim Fname As Variant
Dim N As Long
Dim FnameInLoop As String
Dim mybook As Workbook
Dim myRange As Range
Dim myRange2 As Range
Dim EntireRange As Range
SaveDriveDir = CurDir
MyPath = Application.DefaultFilePath
ChDrive MyPath
ChDir MyPath
Fname = Application.GetOpenFilename(Title:="Select a file or files", MultiSelect:=True)
If IsArray(Fname) Then
With Application
.ScreenUpdating = True
.EnableEvents = True
End With
RangeSelect: Set myRange = Application.InputBox(Prompt:= _
"Please Select the Column you wish to Interpolate. ", _
Title:="InputBox", Type:=8)
If myRange Is Nothing Then
Else
myRange.Select
End If
For N = LBound(Fname) To UBound(Fname)
FnameInLoop = Right(Fname(N), Len(Fname(N)) - InStrRev(Fname(N), Application.PathSeparator, , 1))
If bIsBookOpen(FnameInLoop) = False Then
Set mybook = Nothing
On Error Resume Next
Set mybook = Workbooks.Open(Fname(N))
On Error GoTo 0
With Application
.ScreenUpdating = False
.EnableEvents = False
End With
Columns("A").Select
Selection.TextToColumns Destination:=Range("A1"), DataType:=xlDelimited, _
TextQualifier:=xlDoubleQuote, ConsecutiveDelimiter:=True, Tab:=False, _
Semicolon:=False, Comma:=False, Space:=True, Other:=False, FieldInfo _
:=Array(Array(1, 1), Array(2, 1), Array(3, 1), Array(4, 1), Array(5, 1)), _
TrailingMinusNumbers:=True
'Here is where I think I should reference RangeSelect Somehow!!
'Something Like Workbooks.("Otherworkbook").Activate then make active range = RangeSelect
Start = ActiveCell
EndRow = Range("A" & Rows.Count).End(xlUp).Row
Do Until ActiveCell.Row = EndRow
Selection.Offset(1, 0).Select
'Perform my macro function below etc
If someone can think of a way to do this it would be great! Any more info needed Please Ask!
Tom
Edit:Essentially I want to reference the active range of a 'Master Workbook' and select it in a destination workbook without an absolute reference!

Answer 1

Something along these lines. Note you don't need to Select ranges in order to work with them...
Dim c As Range
'using .Cells(1) in case user selected >1 cell
Set c = mybook.ActiveSheet.Range(myRange.Cells(1).Address())
EndRow = Range("A" & Rows.Count).End(xlUp).Row
Do While c.Row <= EndRow
c.Offset(1, 0).Select
'etc....
Set c = c.Offset(1, 0)
Loop