Basically, in case you need the timeline axis and the scrollbar, you can use a combination of two controls - RadTimeline and RadDataBar. The idea is to use a dataBar control in the template of the timeline item to visualize all periods that you want to overlap. We use this approach in our First Look demo.
On the other hand, in case you simply need a control to visualize a couple of overlapping periods, you can use only RadDataBar. Please refer to our online demos for a quick overview of the control.
All the best,
the Telerik team