Two active sprints (simultaneous)

Need to divide items (stories/epics/etc) into two divisions based on infrastructure.  One needs to support tool development and the other one to support customer specific development.   The tool development is handled on a two week sprint where the customer development is handled on longer sprints where it does not fit within the tool development side.  Need to be able to transfer items (tasks/stories) between the two sprints...for example, if a customer story requires tool development task to be done.  Affects broconne/SDE users.