In the conference scheduling example, add 2 new soft constraints (in DRL and Parametrization). Make sure their weights can be configured in the xlsx just like the other soft constraints.

• Track room stability: Maximize the number of talks of the same track in the same room.
  • Anti-load-balance (= anti-fairness, see docs about fairness) the number of talks of the same track per room.
• Sector room stability: Maximize the number of talks of the same sector in the same room.

Look at the tennis example. And my blog article: https://www.optaplanner.org/blog/2017/02/03/FormulaForMeasuringUnfairness.html
The tennis example has a rough accumulate function that we'll probably want to reuse...