Principles and Constraints.
I have always observed out that setting principles (design or product) is a great way to handle differences. The generic advice of not taking it personally, listen more etc. is still relevant, but most of the creative work is complex by nature - specifically when there is collaboration.
Writing down principles for your outcomes or customers or business is a great way to kickstart and navigate the discussion with variety of ideas.
Writing down constraints helps in holding everyone’s opinion accountable to the discussion. It also helps in thinking the first principles of the constraint and why do they exist in the first place.
Lastly, always facilitate these discussions from a point of curiosity not authority.
PS - Brownie points if you do this in non-boring workshop