Ranking based on subtotal sum and ignoring rows based on criteria

I have a very large spreadsheet. In this spreadsheet I have multiple companies each making multiple purchases in multiple months. I also have listed items that have been ordered and not yet invoiced but with an anticipated ship date. Based on the items ordered I need to project sales for the upcoming months and have only the top 10 customers listed along with all "Other" customers based on their ranking of year to date sales. I attempted a pivot table but could do the sales ranking and the projections but can't seem to get them together. I thought about doing a ranking column to assist but can't seem to get that going either. Note, at this time there are over 1800 rows and 95 columns. I only need to work with 2-4 of these columns.

Any help is appreciated.

Crysaline