Sorry - This whole answer is in there, but got top posted (partially)
and bottom posted in full.

This is the whole answer again:


If I have understood correctly, try this:

0) Backup your workbook(s) nd read all the steps below before
beginning.

1) Autofilter the entire range / sheet

2) Filter 'Customer Column' to show only blank cells (I'll assume this
is column A)

3) Enter a formula in the first cell now showing to refer to the cell
above. For example if you have a customer number in A1 then A7, you
will be seeing A2:A6,A8:A13 etc. In A2 enter "=A1" (without the
quotes).

4) Copy this and paste down the entire range, but make sure that you
choose the option to 'select visible cells only'. This can be put on
a toolbar from the 'EDIT' list if you like: Tools - Customise -
Commands - Edit - Scroll to bottomn of list - Drag 'Select Visible
Cells' to any tool bar you have visible.


That should do it.

HTH,

Alan.