If I open a small business and get health insurance for 3 will they deny any of my employees or myself?

I'm planning to open a business in my home once I graduate but wonder if the insurance companies will deny me or my employees. I understand that in California they cannot deny coverage for employees however I'm wondering if they can do this for a startup company.
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Group health plans mean everyone must be accepted. Because their are only 3 employees, you will likely receive the maximum surcharge, which is 10% above manual rates.
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