If you were going to hire them as employees, you could have them sign a noncompete agreement upon hiring them. However, if they are IC's, having them sign a noncompete would risk turning them into employees under IRS rules. Many small businesses
get in trouble with the IRS because they hire people as IC's but in reality, they are treating them as employees. When the IRS discovers this or the individual complains to the IRS, you would be liable for back taxes, withholding, payroll taxes, large penalties, etc.
Here is a brief article from the IRS website which explains further the difference between an IC and an employee.
See also Publication 15-A which can be found on the IRS website as well.
Essentially, if you impose demands on an independent contractor, they cease to become an IC since one of the key terms is "independent." As soon as you tell the person what they can or can't do, they automatically become an employee.
Because of this, you would would definitely want an employment attorney who specializes in contracts
to review any agreements that you intend to have your employees or IC's sign.