SEI count of entries in a worksheet

I have a list of suggested and firm workorders in an SEI worksheet coming from the ORDERS table. Very straightforward. What is stumping me is I'm trying to make a column that counts the number of work orders that have the same product as the current record. An example would be a column called "# of Workorders" So if there are 5 lines in the report for product "ABC" each line would have "5" in the "# of Workorders" column. Has anyone done something like that? Like an invoice report that counts the number of invoices for each customer?