Test with completion score and inability to miss specific question

My experience thus far has been with creating tutorials with assessments that require a minimum completion score. In this case, the client wants two conditions - to require a minimum completion score of 85%, and to require that a specific set of questions can't be missed.

If the learner were to attain the minimum completion score of 85%, but miss one of the questions they identified as critical, the learner would fail the assessment. I think I might be able to set something up with  variables, but am concerned about reporting the completion status and score correctly to the LMS.

Has anyone had any experience with testing similar multiple conditions and having it report to the LMS? Any best practices or tips to share based on that experience? (The LMS is Blackboard, in this case.)

Thanks!