[SalesForce] Contacts with Multiple Accounts /Multiple Email addresses

EDIT : Saying all this, I just tried it, and, like you said, it seems to attach the Email from outlook as an Activity, rather than an HTML Email, which I assume is the key to tracking. So unless there is a way to attach the Salesforce2Outlook email as HTML Email, its unlikely.

It is an idea, so surely not possible then

http://success.salesforce.com/ideaview?id=08730000000BrXvAAK

Most email tracking works by using a one pixel image, a link to which is embedded in the body of the email. This link is to an image stored as an externally available 'document' on your Salesforce org. So when the recipient opens the email, the link is accessed, which is used to track the email.

In theory if you were to insert this img link tag in your HTML email that you send from the Outlook Connector, it should still work as usual.

Here is a resource explaining how this works with templates http://www.shellblack.com/salesforce/sales-cloud/html-email/

However, it goes without saying that tracking is also dependent on the recipient's mail client not blocking out image content, which MS Outlook does (depending on security settings i presume).

It's a few months later and I finally found the solution to this problem -- and it turns out it's already built into Salesforce (although I believe it's only available in the enterprise edition and above): Partner Portals. You don't actually have to use the core partner portal functionality, but by activating the Partner object, you automatically get a many-to-many relationship between accounts (which is exactly what I wanted). Here's what I did:

Turn on the Partner object: Setup > Customize > Partners > Settings; then check the box to enable partners and hit save.

Add the Partner Account field to the Account Layout: Setup > Customize > Accounts > Page Layouts; edit the default page layout and just drag the Partner Account field somewhere. It’s actually not editable, but I guess it’s nice to see…or maybe making it visible triggers its functionality (not sure).

To make an account a partner account, you must first create it and save it, and then you'll see a button that says “Manage External Account”; click on it an select “Enable As Partner” – now the Partner Account checkbox will be checked.

Then, the way you link an account with a partner account is you scroll down to the bottom of the account page to Partners related list. Click on “New” and select a partner account, give it a role, and save.

If you want to then run a report showing all contacts for a specific account's partners, you'll need to create a custom report with the primary object being accounts, the secondary object being partners, and the tertiary object being contacts. When you run the report, filter it by the original account, and you'll see all contacts for that account's partners!