I am fairly certain I already know the answer to this, but is there any way that tests scripts in QTP can be run in parallel versus in a series if running on a single PC? My answer is no it can not, but I could be wrong.
That also doesn't allow running multiple tests in same QTP instanced. The only thing you can do is run multiple instance of QTP and run multiple tests. This too can be done through use of tools like sandbox or using virtual machines