Hi cody, and welcome to the forum.
You could use the GetSummary function to grab into each record what the summary value would be for the break field you want (ProductCode, MonthNumber?).
Then perform your search for that field >0 as well (or 'Omit' if equal to zero. Suspect it can't be indexed so may be a trifle slow.
Thank you for the welcome and thank you for the quick response. I may have done something wrong but I wasn't able to use getsummary() in this case as anytime I entered find mode my Has_Inventory field which used the getsummary() function reverted back to null. I'm assuming entering find mode unsorts the records but just a guess. Your input did open up a whole new world however and I was able to use an unstored calculation and a self-join relationship to acheive the same results and was able to find based on that field. Thanks again you've been a huge help.
...or run a 'batch script' to find the 'big set' of records, sort it, and simply set the GetSummary function result into a normal number field. Then search on that, indexed.
Sorry for the slightly misleading reply!
The thought of using a script step to assign the value of my getsummary() totally escaped me, I'll try that out. Would probably be a bit cleaner.