Get your taxes done using TurboTax

My wife and I have 6 adult children and we are trying to assist them in efiling their taxes.  I realize there is a five efile return limit, so my wife and I purchased two separate TurboTax software products, installed them on two different computers, used two separate Turbotax accounts with two separate e-mail addresses.  Given that we are two separate individuals and by dividing our children's returns between the both of us, I would have thought we could do five returns each.  However, as soon as I got to my third return (and after she had done three returns using separate purchased software, separate computers, separate email, and separate Intuit account), I was still told by the software that I could not efile the third return for our children.  Why are we being treated as one individual?  What mechanism is being used to inappropriately identify as just one individual?  Any thoughts out there?