Populating different columns with information selected from the same drop down list?

Hi Excel gurus!

I am collecting data in an excel worksheet in an admittedly unconventional way. I have, thanks to this forum!, one column with a drop down list that allows for multiple user selections. When these selections are made, I would like to have the data populate in columns off to the side automatically so that they can be aggregated. The max number of selections is 4, so I'm hoping that I can get the data to look like:

Column0 | Column1 | Column2 | Column3 | Column 4 | Column 5
1 | A, B, C, D | A | B | C | D

I am also open to suggestions on how to improve the data collection. I'm using the above format because there are 6 different options for Column0 (so 6 different columns), each with up to 4 possible sub-options in Column1 & users tend to get lost when scrolling over on the excel worksheet.

I've attached a pared down copy of the data collection sheet, as my explanation above isn't that great & there's a lot of code behind the scenes.

Thank you!