custom column formula help

lillizard

I'm looking to automate a custom column (or columns) by grouping 2-4 dimensions, and then having the total show up in the 'width' column (figured this part out) but having the individual dimensions separately show up in another column. ie, the example here is 4 dimensions, they are grouped together with a total width of 299; I'm looking to have the 4 dimensions of 71, 77, 78, and 73 automatically populate in another column (or columns) every time I group a set of dimensions, specifically into the Band Sizes column. Open to having these automatically populate into different columns as well, just want the automation here.

see screenshot attached. Is there a formula I can use for this? I found a way to use a formula to take the total and divide by Band Count but that doesn't work in this case since the grouped dimensions are all different.