Removing inner borders.

[Ergeiz]

Ive been trying to remove the inner borders, but they wont seem to go. (without losing
the frame borders (the outer borders of a block as you will), as demonstrated in the attachment.

I hope someone will be able to help me out on this, thanks in advance gentlemen and gentlewomen.

[WEBDosser]

styles manager Sizes and Dimensions

Inner Border Width (pixels)
(This value specifies the width in pixels of the inner-border of all colored tables)