Are BPMN sequenceFlow allowed to reference specific activities within another process/subprocess?

Question

I am modeling a complex process using BPMN 2.0 I have split the process into multiple global processes which can reference one another through call activity.

However, in one or two special cases, I would like to actually call directly into the middle of one of the other processes. I do not want to have to create an entirely duplicate [sub]process with just the first couple nodes missing and would also prefer not to split those couple nodes into their own little process.

I don't think common BPMN 2.0 tools support this, but is it explicitly disallowed by the spec? For instance, I read through http://www.omg.org/spec/BPMN/2.0.2/PDF and I don't see anywhere that it claims that a sequenceFlow's targetRef must be within the same FlowElementsContainer. Maybe it is just implied?

Answer 1

The correct way to do this would be to create several "none" start events in the global process and then reference the correct one via the targetRef attribute of a sequence flow incoming to the call activity. The spec says on p. 239:

"If the Process is used as a global Process (a callable Process that can be invoked from Call Activities of other Processes) and there are multiple None Start Events, then when flow is transferred from the parent Process to the global Process, only one of the global Process’s Start Events will be triggered. The targetRef attribute of a Sequence Flow incoming to the Call Activity object can be extended to identify the appropriate Start Event."