our site default email address appears at the bottom of the site generated emails (mass invite e-mail, etc)

i receive - at my personal e-mail address- the emails generated by the site after classmates use the "Missing Classmates" function

I would like the site default email address to receive these site notification messages generated after classmates use the missing classmates function.

how do i make this happen?

You are receiving class email at your personal email address because you are also a Classmate, thus the emails would go to whatever email you have in your account. If you want those emails to go somewhere else, then you would need to change your own email address on your Details page to be consistent with the default site email address you have set on your Preferences page. Note, if you do this, then you would also need to log in using this email address.