List Building Growing Pains (...Can I Have Your Opinion?)

Hey all,

I'm at the point where I've began experiencing what I'd consider to be some "growing pains" with my lists. I was hoping to get some honest feedback on what YOU do in your own business, if you've experienced this before.

Here's the deal:

I've launched a handful of products in the IM niche now (WSOs and otherwise) and for each product I've created a new list in my Aweber account. I like to keep the marketing and follow-ups tightly targeted, and usually structure 5-7 follow-ups with extra content, unannounced bonuses, related offers, etc.

Where the problem comes in is when I launch something or run a promotion and want to tell more than one list about it.

If for example I create and launch a new WSO and email my lists, the people that have bought more than one thing from me will be getting between 2 and 4 emails about it.

Problems with that:

1) it's too many emails
2) the promotional email will vary between lists in most cases, which can cause confusion

Now, I'm obviously familiar with the automation rules in Aweber and would normally use them. But, I promote certain offers to certain lists and if I "removed one from list A when they subscribed to list B" after they bought product B, then what if I want to run a promo for List A subscribers?

Dilemma.

What do YOU do to prevent this?

Here's a solution I was thinking of:

Create a "Main List" and subscribe them to that main list via automation rules when they subscribe to a sub lists (ex: A, B, C, etc... which signify purchasing other front-end offers).

Run major promos to the Main List, and only blast targeted promos to the sub-lists.

Another question from that: is it ethical to auto-subscribe to more than one list at the point of purchase?

Business is awesome, and kinks are a part of the process I guess.

Thanks for any opinions everyone.

-Tom