Concatenate If...

Hello,

I am trying to figure out how to Concatenate a group of cells if they contain a certain text. Basically I have a list of Architects in column A and the account name in column B... and I want to say Concatenate column A, IF column B=Specific Account (ex: Coca-Cola). The list will be added to frequently so the formula must refer to the entire columns, not just a certain range.

As of right now, only the first architect associated with each account will appear. I have attached a workbook with the example.. please let me know if any of you can help. Thank you