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The TargetTransition references a transition that is the target of a branching.
The ConditionOID references a ConditionDef element defining a condition that needs to be evaluated at the time of entering the branching state.
An example may be that the target of the transition may only be executed when a lab result for a specific lab test has been received. Then, until the lab result was not received, the start of the target is "put on hold". For transitions that must be executed after a specfic given time, use TransitionTimingConstraint. An example may be: next test must be done after 10 minutesWhen the condition evaluates to true, the branch is entered.
When there are several conditions at the branching point evaluating to "true", the corresponding branches will be entered. This will then usually lead to parallel activities.