How to change just one side border width of a ttk.Entry?

  python-3.x, tkinter-entry, tkinter-layout

I am trying to display a sudoku layout with tkinter grid and ttk entries (maybe, I am not using the right approach to achieve it). I would like to know if the style option of ttk entry has any way to change the border of just one side. I have applied this function:

def grid_layout(parent):
    s = ttk.Style()
    for row in range(1,10):
        for column in range(1,10):
            entry = None
            if column % 3 == 0 or row % 3 == 0:
                entry = ttk.Entry(parent, width=3,justify='center'
                entry = ttk.Entry(parent,width=3,justify='center')
            entry.grid(column= column, row = row)

Which produces the following view:

enter image description here

I just need to change the border width shared by colum 3-4, 6-7 and row 3-4 and 6-7 ,as the typical sudoku-like layout. Any recommendations would be appreciated.

Source: Python-3x Questions