Subscribe by email from address in multisite install

Hi,
I am after a bit of clarification on how the Subscribe by Email plugin functions for a multisite install. I am hoping you can tell me how the Notification from Email setting works. Is this one email address for all of the sites in my multisite install? Or is it possible to have an individual from address for each subsite?

For example I'd like to be able to set the from address for blogs.otago.ac.nz/test1 to an address like test1@otago.ac.nz and the address for blogs.otago.ac.nz/test2 to an address like test2@otago.ac.nz.

Is this possible? Or do I instead have one address no-reply@otago.ac.nz for every subsite?

Thanks in advance for any clarification you're able to provide.