I wish to conditionally format a range (say A1:A1000) with the following
criteria;

For each cell in the range(A1:A1000), how many of the other cells in that
same range, share the first 4 characters - if greater than 1; format.....,
etc.?

I looked at the countif function, but couldn't find a way to apply it and
I'm stuck for alternatives.....

Any bright ideas?