As a user experience designer, aside from being a advocate for user needs and business objectives, should be a good communicator among different teams, especially if you want team onboard with your design decisions.
My experience: before a group design review meeting, communicate the design ideas offline to get input with key reviewers individually (or in small groups), this ensures that 1. They offer your their expertise and new ideas; 2. They help you check if there's anything unrealistic or out of scope.
The most important reason for having these conversations is that your design decisions do not come as a surprise to them, because surprises can stir discussion and take up time in your design review meetings. You want to address as many potential questions as possible offline, and only leave those worth group discussions in the meeting. This way, you save everyone's time and can end your reviews on time.
