“You have to manage a salesperson’s ego.”
That is just crazy! Ego is someone’s view of themselves, you can’t manage that.
You can lead a salesperson to hold up their metaphorical ego mirror and bring them to the path of working toward a healthy ego. They have to be willing to walk down that path on their own – you can’t manage the ego work they choose to do or not do.
What you can manage is the task of appropriate ways to interact with other people and departments. You can hold a salesperson accountable for the communication style they chose. You can ensure they understand the implications of not being aligned with people they work with.
This isn’t simple as you do both at once and it certainly isn’t easy to accomplish with every salesperson on your team.
One option is to include conversations about ego in your regularly scheduled one-on-one meetings so the salespeople on your team are used to the conversations.
That way it is less uncomfortable if there is a behavior correction conversation that needs to take place. Plus those one-on-one meetings may be the minor course correction needed to eliminate something happening that requires behavior correction.