Well, the IRS is now getting a little tough with sole proprietors and small businesses using contractors to perform service work for them at your sole direction and direct supervision and then classifying them as independent contractors!
If the independent contractors work exclusively for you, then you may not meet the test for being eligible to consider the contractors as independent contractors. I suggest that you perhaps at least employ 1 of the contractors who works exclusively for you under your sole direction and guidance.
Please also review the following link below to determine whether or not your employees qualify for being treated as independent contractors. Will your employee's status as an outside contractor pass the IRS litmus test?