You can follow following,
1. use fep_form_field_output_fep_pro_to action hook to create a checkbox in “To” field
2. use fep_form_field_validate_fep_pro_to to check if your checkbox is checked, if checked than you can query your group members on the fly and added in $_POST['message_to_id'] as array.
3. You may need to use fep_errors()->remove('pro_to') in fep_action_validate_form hook

Note: I will try to add Group messaging feature in next major version.

“Hi,

I really need to be able to create groups / distribution lists for sending messages. I have a custom have user field that defines the groups I want to use, so I just need to query by that field to build the recipient list on-the-fly (I don’t need any be able to pre-define the groups directly in Front End PM). I don’t mind adding a custom function or filter or two if necessary, just need some direction about how to get started or if it is even possible using Front End PM Pro.

Thanks!”

+1
This feature saves a lot of time and avoids recipient errors. We hate it to be developed.
thanks

It is already in our TO-DO list, also we are working on this. May be next major version we will be able to include this feature.

Thanks

As this is an old topic, it is always better to create a new topic so that i do not miss.

You can use fep_get_option to give permission only to admins to send group message.