I have a spreadsheet with multiple rows. I have multiple rows for a
given ID which is shown in Column A. I want to group the rows with the
same ID visually by using color bands. The bands should also
alternate.

For e.g. if my data (in column A) looks like the following

A
A
A
B
B
C
C
C
C

I want three rows with A to be shaded in grey. Two rows of B to be
white and 4 rows of C to again in Grey. The number of rows may vary by
the data that is loaded.
Is there a way I can use conditional formatting to do this?

Thanks,