Impossible Goal versus practical constraints

Earlier this year I joined a new organization, and my goal is to get a promotion, (in fact, my impossible goal is to get two promotions and reach Senior Director level). However, the organization has a strict policy preventing people from applying for promotion until they have completed at least two years in a position. That means I’m not even eligible to apply for a promotion for another 18 months. How do I stay focused and pursue my goal when there is this practical barrier?