This Business Process Model and Notation (BPMN) Choreography diagram demonstrates how to define a group template to look like a node template, with a rounded header and a rounded footer.

The "RoundedTopRectangle" and "RoundedBottomRectangle" figures are defined in RoundedRectangles.js in the extensions directory. See also the Two Halves sample and the Parallel Layout sample.

We also have a BPMN Process Editor sample.