In this article, the authors introduce a new feature to model the collective bargaining process: a two-level game setting with direct learner-expert interaction. In the simulation ZUG UM ZUG 2015, participants form union and management negotiation teams to negotiate with each other (first level) and with a management or union "tariff commission," which has to approve proposed contracts (second level). To increase the degree of realism and the teaching effectiveness of the simulation, real-world negotiation experts negotiate in tariff commissions directly with participants. The authors also introduce a negotiation process to facilitate an efficient knowledge transfer from experts to learners. (Contains 3 figures and 1 table.)