create testcase list for iterations/future relases

We would like to be able to identify in a comfortable way all test cases which have to be executed for an iteration, in order to create a testset for this iteration.

Suppose we have 500 requirement assigned to a version 2.0, 300 of them have been completed / implemented for version 1.1. and the developers have changed the release property of all this requirements to 1.1 manaually. This permits to filter all completed requirements for iteration 1.1

Now how can we display list of all test cases assigned to these requirements in order to

assign them a mapped release 1.1 using the function "Add to release", without editing each test case one by one what would be very painful.

The only workaround we saw, is to create a report with attached testcases, but this is also not very suitable.