Note that, while it is not especially easy, you can already do this: from the Query Builder tab of Pupil/Student Manager, in the data field box drop-down scroll down until you get to the Student Contacts section of the list and pick either 1st Email or 2nd Email. Used with the Like Query Type, this allows partial matching too, so you can find everyone whose parent uses a gmail address, for example.
Note that, while it is not especially easy, you can already do this: from the Query Builder tab of Pupil/Student Manager, in the data field box drop-down scroll down until you get to the Student Contacts section of the list and pick either 1st Email or 2nd Email. Used with the Like Query Type, this allows partial matching too, so you can find everyone whose parent uses a gmail address, for example.