Ability to associate a set of change requests to a parent change request

The current spec allows one to associated one or more change requests with the current change request either as a neutral association (relatedChangeRequest) or to inform impact analysis (affectsPlanItem) or as a decomposition (affectedByDefect). None of these relationships represents a container relationship whereby the current change request is decomposed into a series of tasks that must be done in order to satisfy the change request. This is a significant gap that can't be filled by repurposing one of the existing relationships because a) there may be a need to represent one of the other relationships in addition to a container relationship and b) there is no easy way to indicate how the client should interpret the relationship anyway. Note that task order is significant - not sure how it should be represented. Finally, there is (probably?) no need to include the same task twice on the same list. However, I can see a need for a task to show up on multiple containers so that it can be completed by the first person to get to it.