To be truly XRM capable, we lack customization capabilities on the RollupRequest message and ActivityPointers. In different customer engagements, we share the same feeling that these two platform concepts are non-extensible or non-customizable, probably with good reasons (taking performance as one of them). But in the end, if you would like to build your own application line into the XRM platform, the limitations on extensibility do create a drawback. 1) Activities(pointer) - not possible to: a. Add a field b. Change icons c. Attach custom logic on other platform messages then Retrieve and RetrieveMultiple d. Disable unused activities (eg. Fax) e. � https://msdn.microsoft.com/en-us/library/gg309626.aspx 2) Rollup Activities (NOT related to Rollup or Calculated Fields - http://survivingcrm.com/2011/06/crm-2011-subgrids-aint-what-associated-views-used-to-be/ )� not possible to: a. Attach custom logic onto this message b. Add or Remove Supported/Target entities (possibly related to the lack of not having a Customer lookup related) for building or adding your custom XRM logic. https://msdn.microsoft.com/en-us/library/microsoft.crm.sdk.messages.rolluprequest.aspx