Since there is only one app, it is not possible to use google or facebook metrics to provide separate report for each organization.
Do you think it will work for you if we send app usage statistics in email on monthly basis?James Houston commented
I have already mention my response over here but it has been hide by the moderator.James Houston commented
It is little bit wake question because you didn't mention that with what platform you are willing to measure it. Although there are facebook app metrics, google play store metrics and other metrics which depends according to your online store. However with analytics you can easily measure that how many new member are using your app Here is guide on it: https://support.google.com/analytics/answer/2587086?hl=en
For facebook Metrics: https://www.withintheflow.com/important-facebook-metrics/