May I receive departmental statistics from the EAP monthly report?

Hello. Our company, with approximately 450 employees, is considering implementing an EAP next year. While comparing proposals from different vendors, we were informed that the monthly reports can provide not only the total number of uses but also usage status by department.
While checking figures by organization seems helpful for identifying and supporting high-stress departments, I am concerned that departments with 10 or fewer employees or those with only one monthly user might allow for the estimation of counseling users. If counseling topics or age groups are also categorized, the risk of re-identification may increase further.
We are currently reviewing measures to establish a minimum number of personnel to count and to either group departments that do not meet the standard with others or include them only in company-wide figures. Additionally, we do not plan to use departmental usage rates for the performance evaluations of individuals or team leaders.
How should the minimum number of personnel be determined when receiving departmental statistics in the monthly EAP report? I would also like to know the scope within which the company is permitted to verify items such as usage volume, counseling topics, and gender/age groups, as well as the criteria for aggregating small departments.