Is it possible to sync subscriber lists between Subscribe by Email and Email Newsletter Plugins?

OK, This question applies to a couple different Clients' sites, including the following:

geofjowett.com
letstalknevada.com (letstalknation.com)
acewebsitepro.com

Is there a way to sync subscribers automatically to both lists? For example, a subscriber signs up to receive new posts, I'd like them to automatically be signed up for newsletters also. And when someone unsubscribes, I'd like it to be from both lists.

I have been having an error on geofjowett.com where when he posts a new blog, the email does not go out as it should, it says user content empty. I have tried deactivating and reactivating the subscribe by email plugin to see if that resolves the problem, as it did work the first time I sent a message, but the most recent few have not gone out. I have enabled access to Geofjowett.com for your convenience, I'd greatly appreciate if you can take a peek at the settings on these two plugins to see if you can find anything that could be causing this error.

Thanks a lot!
Jay