Change number of columns on specific element in 2-columned layout

Hi everyone,

I know there is a way to change the number of columns on a specific element. Problem is, that there (imao) are not enough options to specify the way columns should layout.

Now what I am trying to do is to change the number of columns in a 2-columned layout to 3 columns on e.g. element ul, where one of the original 2 columns should split into 2 columns, whereas the other shouldn´t change.

So the ratio should be 25%, 25%, 50%.

Anyone ever did something like that successfully?

Hoping for some help

Daniel Thursfield