that works as long as your 3 co-founders are relatively healthy and have been healthy their whole lifes, if one of them develops a problem you can expect your premium to skyrocket into unaffordability
Group health care plans (what your employer gives you) are given largely without consideration for the health of the individuals involved. Basic tests, like making sure you don't have a major heart problem and pee tests are involved but thats it. Friends of mine who have a business with only 3 employees listed me as one of their employees to get the number up to four. Some how I was registered whilst living in another country.
And I believe there are already laws on the books about pre-existing conditions (assuming you have continuous coverage)