Grouping without reducing

I’m using Redis to store file metadata. I am trying to search and group results but without aggregating them. I’m not sure if this is possible. The file metadata is stored as Redis hashes. I want to be able to search for the value of a field, like size, and have it group all of the objects of the same size. If I use aggregate and groupby with reduce, it will give me a summary of the groups:

ft.aggregate idx:files '*' groupby 1 @size reduce count 0 as nb_of_items limit 0 1000

but that’s not what I want. I’m new to Redis so I maybe my index or structure needs to be reworked. Is this going to have to be multiple steps handled client-side?