Setting global variables or updating data values in a dataset

#1

I have 2 tables which are joined by a third.

  1. Property
  2. Agent
  3. Agent_Property (joins Agent with Property)

Agent_Property table has a column for commission_percentage. For each property in the Agent_Property table, the sum of commission_percentage for all agents need to equal to 100. The number of agents a property has is random.