Border on specific columns

[lkoehl]

I am currently facing the problem to add borders to my columns. Is there an easy way to add a border to specific columns?
Otherwise let me explain my problem in more details. Below you see my table I created with react-table. There are two colums with Input and Output and each one of the columns have n subcolumns. The amount can change over time. What I would like to achieve are borders on just the last items in every column to have an effect like you can see in the picture (black lines are drawn with paint). I would be very grateful if you can help me out.