How to color the gridlines of a datagrid column

Question

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Hi,

I have a datagrid filled with rows and columns

I have a one column that contains no data and thats has another color, gray
but for that one column it would be nice if I didn't see the gridlines of that column
so I want to 
- give the gridlines of that specific column the same color as the column (gray)
or
-don't show the gridlines for that specific column.

any idea's ??

thanks in advance

Greetz