Limit number of UICloudSharingController shared users?

I'm investigating leveraging the CKShare functionality provided in CloudKit to share data across multiple users in my iOS app. However, I only want a user to be able to share with a limited number of users. Is there a way to constrain UICloudSharingController to a maximum number of X users? I don't see any properties in UICloudSharingController that jump out at me. Nor did I see anything in UICloudSharingControllerDelegate. Any ideas?