Running total of multiple running totals

I have a production workbook of 7 worksheets. The first is for data entry for leads and consists of various information. This info is transferred to the 6 other sheets, depending upon content. There are 5 agent sheets and one sheet for closed transactions (a total of 7).

Now...on each of the 5 agent sheets, there are columns for financial information, including commission totals. The last columns are running totals of total production and commission. The most important is the last column on each agent sheet, called "Gregg's Commission Running Total" which totals the column titled "Gregg's Commission."

On the closed transactions sheet, the last column is also labled "Gregg's Commission Running Total." That is because I need this column to be a running total of all 5 of the others. I need the running total for Gregg's commission on the closed transaction sheet to be like a live feed of all of his commission. The agent sheets will be updated and their totals will change independently of each other. I need the running total on the closed sheet to reflect this. If anyone needs anymore info or clarification let me know, I've attached a sample workbook. Thanks so much!