Specify the entities that compose the activities - CRM 2015

Question

I need to specify the activities entities on dynamics crm (2015). Specifically, what i need is to limit the option set on Case activity. In this form, i want to let the user add just "Service Activity". I searched ways to change the data for Case entity (which i understand as the best solution), customize the form (i did not find any form that could be related) and even mark the others entities as non-activity entity (however, the dynamics crm doesn't let me, due to the fact that this check box is disabled on entity customization). Is there an way to solve this issue ? (The specific view is in the image attached 1).

Thanks

Answer 1

This is not possible. You can however customize the ribbon of the associated view. Hide the Add New Activity button and create a custom button, e.g. titled Add New Service Activity.