Looking closer at the code, I see you are using the DonorBackingForm, instead of FindDonorBackingForm. Validation should still occur in a *BackingFormValidator class. Since the standard form to search for donors does not require validation, there is no corresponding FindDonorBackingFormValidator. 

It is not really correct to map the search fields to `DonorBackingForm.getDonorPanels()` and `DonorBackingForm.getBloodGroups()`.

My suggestion would be to create a new `DonorCommunicationsBackingForm` to map/bind the fields used in donor communications, as well as `DonorCommunicationsBackingFormValidator` to handle the validations. Please refer to similar `find` methods and `Find*BackingForm` objects to see how this is done (although this search is unique in that it requires validation, none of the other searches appear to require validation.)