Marking Release for a Work Item

We have a team who's work spans both a new release and maintenance release cycle. That is within the same sprint the same people may need to work on a new release item and/or a maintenance release item. We're using RTC and would like to track this so that we do the plan by sprint but see in the view which Work Item (Story/Defect) is for which Release. This will also help us do some early planning on future sprints to prioritize field issues or potential work.
I see this as slightly different than the planned for field. We may have several different maint releases and we don't necessarily want to create a new plan for each of those and duplicate the team across all those plans, as our product has a 5 year support cycle. So, I'd like to use Planned for to indicate the actual timeframe (aka Sprint) the work is done in but use a "Release" field to indicate what release the work is actually for.
Is there a way to do this in RTC? Or does anyone work on a team that has the same sort of new release/maint release workload and have found a good way to track them?