Setting up Roles for Global users

I'm hoping someone can give me some recommendations. Our company is global and we have users in the UK. When assigning people to roles on tasks, is there a way for the UK users to only see roles of people in the UK. For example, if the task is assigned to a Producer role, when they hover of "Producer" for names of producers, it shows them ALL producers in the company in all regions. I'm wondering should I set up roles called, UK Producers, AMS Producers, APAC Producers. Any suggestions would be great. Leslie Tanner