Procedure to concatenate names in an office into one cell

I need to develop a procedure to concatenate names with a carriage return. I am doing this so I can import them into visio so I can create an organization chart showing the office and all the people assigned in the office. I used a concatenate function from this forumn earlier to do this but it still will take too long I would like to cycle through each office and concatenate all names into one cell. the Function works great, but I need to automate it since I have over 500 names to concatenate. I have included a spreadsheet showing what I want to do. I know it will involve a loop for each office. Thanks for you help