Is it possible to delegate parts of a questionnaire?
Yes. For more details, see Delegating a Questionnaire.
Is it possible delegate “context 1” to “user A” and “context 2” to “user B”?
Yes. You have two possibilities:
• Divide the questionnaire into several questionnaires (1 node per questionnaire).
In this case you have to set up a rule to deduce users A and B.
• Build a single questionnaire for all contexts and send this questionnaire to users A and B.
In this case you have to define display conditions to hide questions (the conditions may apply to the context objects of each node).
See also Conditions on question display.