Calculating number of instances running at once

im currently coding a cBot that takes account infomation about the current ballance, equity, etc... The bot is designed to work out by its selft how much of the account it is alowed to risk at any one time. however one key component that i am yet to figure out is how to account for more than one instance of the robot running at once. For example if i say that the robots are allowed to risk 20% of the current ballance and there are 4 bots running i wish to have each bot only use 20/4 (5%). Any help on how to go about this would be much appriciated. 

Thank you

William Daley