How to create parallel approval within a single stage

To create a stage with simultaneous concordance among several users, do the following:

1. In IWorkflowRuleProvider, register a rule to check the user access rights to concordance. The access should be defined by taking into account concordances previously executed at this stage. Executed concordances are recorded in WorkflowProcessTransitionHistory table.
2. Add a record into the "Actors" block with a rule from step 1.
3. Add a cyclical Transition to the current Activity with the following parameters: Trigger Type: Command, Restrictions: Actor from step 2.
4. In IWorkflowActionProvider, register an Action that will check whether or not the stage has been fully concurred. Executed concordances are recorded in WorkflowProcessTransitionHistory table.
5. Add an outgoing Transition from the current Activity with the following parameters: Trigger Type: Auto, Condition Action: Action from step 4.