Parents with multiple students can receive emails for each individual student when sent to the student

We send out extra competition offers and they are generally on an individual basis. We have parents who have multiple students here and when I select the students and send the individual email to the students (using the parents email), only one copy is sent to the parents instead of multiple. I know it sounds redundant to receive 3 emails that are the same but when we offer 2 of the three children or even all three children offers, I want the parents to know that it is for each student so they aren't left guessing who the offer is for when they only receive one email.