It won't be perfect, but you can adapt when you have to. They need to know that what they are doing isn't just ending with what they are doing immediately. Not everyone needs to know every detail of the five year plan, but it helps if they know that you have one. Different groups will have different power at different times, but all groups need to be heard and represented. This increases the diversity and quality of the information, thus improving the quality of the decisions.
Information needs to flow freely around the company.
This prevents isolation of groups and people, and ensures that the decisions are informed. It allows adaptability and the ability to measure progress in a timely manner. We need to leave egos at the door and keep people focused on a common goal, the company's success. Thus an individual needs to be professional because that has more value to the company, and thus themselves, assuming the company is well run. Say it clearly, then do it.