Sum If - Finding Average for similar company name

Hi All,

My spreadsheet is calculating monthly revenue per building and averaging that cost in column p.

Each building belongs to a different company.

I would like to calculate the average of all buildings belonging to each company.

Example. I would need to average the cost of all buildings belonging to company “1”. I would need to average the “averages” in column “P” for rows 2, 3, 4 and 5. I would need to do this for 2000 buildings/1000 companies.

Any suggestions?