Whenever I try and reply to a message sent to a email group (in which my school email address is a member) I get a message that says my reply was unable to be delivered becuase I am not a member of the group (my school email is a member, my gmail is not). I have my school address forwarded to my gmail, and my gmail is pushed to my pearl, so I am receiving the group emails. My gmail settings are for my replys to be from whichever address the email was sent to, but whenever I try and reply from my pearl it sends them as if they're from my gmail address instead of from school email address so they are not delivered because my gmail address is not a registered member of the email group.

Anybody know how to fix this? Does it matter which email address is set as my default under gmail? I hope I wasn't too confusing, any help would be greatly appreciated.