A facilitator should not be from within your organization or even from your industry.
Either of those bring their own issues and conclusions which are fine when they are working within the team. However, if they are facilitating the process they can unduly lead the group in their predetermined direction.
Example: a Chamber of Commerce brought in the executive director of another Chamber as a facilitator. He pulled the discussion right along but the product was more suitable for his town than for ours. They pulled in a business instructor from the Community College to facilitate another session. The resulting plan worked very successfully.