Short answer is no—that is beyond the usage envision by the plugin.
Long answer: We can still do it. With a service like MailChimp, you can setup multiple groups on for your list (MailChimp tutorial) and then add the "extra" code to the Hidden Fields form in the plugin (as it accepts any input html tag).
The styling may need to be tweaked, as this wasn't foreseen when the StudioPress themes were developed, but technically, it should work.
With MailChimp, you'd need to setup an RSS->E-mail campaign for each of the RSS feeds, set to be sent to the specific group within your list. Once all that is done, you can get the signup code from MailChimp. That code can be dropped directly into a text widget or we can drop it into the plugin if you want to make it easier to get it to the established styling.