The difficulty of the relationship is not the legal standard. Explain the applicant’s special or advanced organizational knowledge and how the proposed U.S. work uses it.
Identify the knowledge behind the customer result
Describe relevant methods, adaptations or processes and the applicant’s actual capability. A strong customer reference may establish a result without explaining the knowledge involved. Neither exclusivity nor general recruitment difficulty is a universal prerequisite or substitute.
The organizational relationship and qualifying employment period require their own evidence even when the customer strongly requests this particular employee. Hypothetical example: A Trois-Rivières precision-optics calibration technician is requested by a U.S. customer because she knows a difficult instrument line.
The first review should identify the organization-specific calibration methods, decision rules and prior assignments that she actually knows, then compare them with ordinary technical skill. A customer request may explain urgency but does not establish specialized knowledge by itself. The records that settle the point can include training history, technical work products, knowledgeable descriptions and evidence of the organization’s processes.
Do not substitute recruitment difficulty, a high salary or a confidential label for an explanation of the knowledge. Sequence the analysis from the applicant’s acquired expertise to the U.S. tasks that require it, while separately verifying the corporate relationship and qualifying employment period.