I have a question regarding user defined iteration types.

Assume we have several development teams working in a synchronized agile release train, for example: iteration, iteration, iteration, release (internal & external): iteration, iteration and so on.

Assume we have a Team Area for every development team and then one Team Area that is parent to all development Team Areas.

Further assume we have an iteration hierarchy so that each iteration in the release train has a corresponding RTC iteration.
At the next level we have on RTC iteration that spans over all iteration between releases.
And finally on the top we have one RTC iteration covering all iterations.

Now, assume we like a plan that will show the real time status of how it goes with the next release (internal or external).

We then would like to see how the progress are for all development teams across the iteration that spans the three iteration defined for the release in question.

A Project Release Plan on the parent Team Area and the RTC iteration covering the three iterations should do the job and show us what we need.

Ok, now to the question:

It would not make sense for developers to be able to assign Work Items to the parent iteration that spans over all three iteration at the lowest level.

Can I use Iteration Types to prevent Users from selecting these iterations when assigning Work Items?

/Torbitz