BuddyPress.org

Now that I have this site built I’m having a hard time wrapping my head around everything related to BuddyPress and how it should operate as a multi-network. So in my setup I have the following:
WPMU, BP, BP Multi-Network, Networks+

I have the following networks:
Main Site: http://teamnu.net
Network: http://active.teamnu.net
Network: http://business.teamnu.net

This continues for a current total of 6 more networks. What I need is for the following to be available:
1. Multiple communities created to target areas related to that community. So the Active community will have groups which pertain to being Active. Same for business and the other network communities. So in other words I need for the groups to be isolated to that community.
2. Each community provides the ability for users to register and purchase blogs, or groups, within that community. This will always be an option but I just want this feature specific to be available to that community.
3. All user accounts are shared across the entire network resulting in a single sign-on.

This is a totally new undertaking so bear with me as this is where things start to get a little hazy:

1. The first thing I’m seeing is that when a user registers they don’t see groups from other communities in the registration form. So what I’m wondering is if there’s a plugin which will pull all groups from across the network and display them in the registration form regardless of which community the user registers with allowing for a true single sign-on? From the way things are looking now users would have to register multiple times to opt into the various network groups. Although I “think” I’m ok as I’m hoping to give users the option of picking what communities and groups within that community they’d like to join I just don’t know if this will become a annoyance. I know I want user dialog to be isolated to that community.

2. If a user creates a new post on their blog by default it appears in their activity wall. I came across a Recent Network plugin which allows you to display the post on not only the blog but also within the community. The problem is that it pulls all info of the info which would normally be displayed on the wall. I just want the post to appear within the community. This way the post appears on the blog and within the community. Is there a plugin which allows this?

This seems skittish but I’m trying to piece this together as I go along so again please bear with me as I do have more questions.