Ok... since Turbine obviously isn't addressing the issues a couple buddies and I did some experimenting (largely thanks to skype communication)
Here is what is happening... When you load into a zone it is important that you load into a zone that does not currently have any hirelings in it. If there is a hireling there when you try to load in, it has a fair probability of causing this very LONG and annoying problem (about 13 to 15 mins of down time every time it occurs).
Work around Example: You are in STK with one of your friends and you each have a hireling... Before you move from part one to part two one of you MUST dismiss your hireling. The same person that dismissed their hireling MUST be the first person to enter part 2.
In other words... If you have an active hireling you MUST be the last one to load into the instance.
I understand that Turbine is busy with many things... but this **** has really ****ed me off. It would be really nice to get official recognition and feedback for this problem.. I keep being told "its fixed" no matter who I talk to... yet it obviously is not. I hope this helps... and doesn't give anyone ideas about how to grief their party members.