This article will show you how to group items by text value in the feed
"Group by" is an action you might choose to make if you have different versions of an item, which causes many repeated lines in the feed - each with its own version.
For example - sizes of a clothing item, or different cities where a hotel chain exists in.
There are 9 sizes for the same product (product title):
Since the values for Title repeat, we will first remove duplicates on the Title column:
Then, we can aggregate them into one line on the Brand column: