OMG is not recommending XPDL for serialization of BPMN, but recommends the use of BPDM.
[There are] some ideas about defining aspects of a process, such as security, escalation and exception handling, in order to simplify the primary representation. The aspects would be invoked whenever an activity is executed, but represented on separate diagrams. In that way, an aspect would effectively be a template for activities that could be overlaid on any of the activities in the main diagram and extend the meaning of the main diagram. Each activity in the main diagram would need a mechanism for passing some number of parameters to the instance of each aspect that may execute for that activity, for example, some measure of the time-criticality of an activity in order to trigger an escalation at the approriate time.