You could try adding a new action to the MS Excel VBO to do this.
If you take a look in there, and examine the code stage for the Format Cell action, you can see that it is similar to the suggestion on the StackOverflow link, which suggests something like:-
Range(""C11"").Borders(xlEdgeRight).LineStyle = xlContinuous
Range(""A15:D15"").Borders(xlEdgeBottom).LineStyle = xlContinuous
(as an example).
So you could try adding a new one called Set Border which takes inputs of the cell range start and end, and then use code similar to the above.