I thought I had this solved but testing proved otherwise. I am trying to do an average of three days of pricing indexes for cargo voyages (1 day previous to the voyage, the voyage day, and 1 day post voyage). The issue I am having is that my voyage dates do not always line up with the dates that the index is published (there is no pricing info published on weekends/holidays). So I may have a list that looks like this:

If I have a voyage that takes place on 12/26, I would just use the pricing for 12/23, 12/24, and 1/2 for the appropriate index. In Excel I just use an INDEX MATCH MATCH with an approximate match instead of an exact match so my 12/26 voyage will return as 12/24 for the average calculation.
How can I reproduce this in Alteryx?