[Mass Email Sender] Select User Level

This question has been asked before, but I'd like to ask again -- Can we have a select box to chose type of users that will receive a particular "mass email" message?

By default, ANY user registered on ANY site receives a message when we send one out. But many of the messages I (the network admin) need to send pertain to the site owner/admin, and not necessarily their authors or their subscribers.

In fact, their authors or their subscribers don't even know we exist behind the scenes in many cases.

For example, several of our (sub-blog) users have MarketPress stores, and when someone registers on their site as a part of the checkout process, they then become eligible to receive the mass emails.

If I just want to send an mail to site admins to let them know we've installed a new plugin, or to inform them about network maintenance, how do I do that? Won't all users on the network will receive it, including subscribers, authors, and contributors?