It is getting more and more difficult to get group health insurance coverage in place. Underwriting with all insurance companies is tightening up. Therefore, it is good to get your group insurance plan when you are small. If you have two or three employees and they are in good health it is very easy to get group insurance. Once your group insurance is set-up it is easy to enroll future employees in coverage, even if they have some health problems. But if you wait and seek to get group health insurance for employees with serious health problems, the insurance company may decline to quote your group.
Of course this does not mean it is impossible to get group health insurance if some of your employees have medical problems. It is still doable but more difficult. Often companies will request medical records.