Fixing Unforeseen Issues

The past two weeks have been a challenge for me. I had a workshop for the IB-MYP for Maynard Jackson and King Middle schools that did not go over well with the staff members. First, here are some background information for you to fully grasp the issue. The MYP spans from 6 to 10 grades which means the program must align between the 2 schools. IB views the High School and Middle School as one program even if they are in two separate buildings. The challenge I have is working with the High School IB Coordinator to build understanding with the middle staff. I have a every good rapport with my middle school colleagues. I know that the middle school staff is enthusiastic about the IB-MYP. However, the High School Coordinator has a perception that our middle school teachers are not doing enough to prepare the middle school students for the IB-Diploma Programme (DP). A video testimonial was presented in the IB-MYP workshop that casted my middle school colleagues as ineffective. The problem with this video is that I was unaware of its negativity. I did not create the video, the High School Coordinator created it. A lot of my colleagues came to me complaining that the video was a gross inaccurate picture of our middle school. One of the arguments against the video was the fact that the High School had the middle school students for 2 years to prepare the for the DP given that the program starts in the 11 grade. I invested a lot of time building relationships with my colleagues. And I was highly upset that this would now create a rift in that relationship. How do I move forward with correcting this?