Hiii school of football asked me to build the school site ,

Hiii
school of football asked me to build the school site , they have different player categories. They want to have kind of subscription for each group in the category ,so they can send an email to a specific group . And if a single player want to send a message to his trainer , this email message must appear to the trainer and to the management department as well.
Which plugin should i use to do this requirement?
They also need to manage these emails at the back end with simple user interface.
Could you please give me your suggestion about how to accomplish the task
Regards