I want to insert subtotals only for items containing at least two specified
costs.

A B C
1 Item Name Cost Title Cost Value
2 Item 1 Cost 1 5
3 Item 1 Cost 2 3
4 Item 1 Cost 3 4
5 Item 1 Cost 4 1
6 Item 2 Cost 1 9
7 Item 3 Cost 3 6

This setup continues for 28,000 rows. I want to separately sum all the cost
values for each item number which contains both a cost 1 and cost 2. Are
conditional subtotals possible, so that only items meeting the criteria would
be subtotaled?

I would also be interested in capturing the value of the corresponding
item's cost 1 in the cell adjacent to the item's subtotal - in this example,
the value 5 from cell C2 would be insertee in the cell next to the item's new
subtotal. What formula could be used for this separate function?

Thanks!