I think you are asking for a VI that is the main VI that does nothing more than launch subVIs. This easily done by using an event structure and having the subVIs show front panel when called. It would then hold until the subVI's run ended. The control would then return to the main VI.
Or you could be asking for a main VI that did not hold that would launch other VIs and they would block each other (the hold being of the other subVIs). This could be done by dynamically launching the subVIs and having then share a semaphore of some sort (semaphore, notifier, queue). The SubVIs would be set for floating. I have not done anything like this but I think it may not be that difficult. Please write back with a few more details.
