Conditional formatting groups of data

Hi all,

I have a spreadsheet with data in a table with order numbers in column A. Although each order is given a unique number, the data populates with multiple rows, one for each line of the order, all with the same order number depending on how many lines where on the order (which is generated via other software and cannot be altered). Therefore the data, when sorted by order number, appears in groups:

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Is it possible to conditional format each line in groups of the same order number to make it easier to differentiate between each individual order which will still work when the data is sorted or filtered? Any suggestions on how to go about this would be very much appreciated as I have been googling all night and making little headway!

Thank you in advance