Search from within a group of customers?

Hi,

First time poster here.


Here is a problem I've spent some time trying to solve.

I'm trying to find a rate of returned items (returned quantity /sales orders quantity) for a certain month. This means finding the number of specific items returned in month Y, which were purchased only on month X.

Because I haven't found a way to link the purchase/return per item transacted, I'm looking for a way to group customers with certain characteristics (ie, purchased on month X), and then search within this group.

So I ask, is this possible to do??

Or in any case is it possible to nest a search inside another search??