Munchkin code across multiple domains, brands and partitions?
We are trying to get our Munchkin code setup and tracking our customers properly but are running into a bit of snag.
Here's a simplified flowchart of how we use multiple brands and websites. The end goal is we want one person's web activity to be tracked within that brand when they visit multiple unique domain names that we control:

Scenario:
Let's say we are trying to monitor the web journey of one Person in Brand 1 and would look something like this:
Send email > Click email link > Visit www.brand2.com (with Workspace/Partition BRAND 1 Munchkin script) > Click www.sharedsite.com link > Visit www.sharedsite.com/page-1 (with Workspace/Partition DEFAULT Munchkin script) > visit www.sharedsite.com/page-1/sub-page (with Workspace/Partition DEFAULT Munchkin script)> etc.
Would we use the Associate Lead API Call to make sure that this Person's web visits are tracked and recorded under their Activity History in BRAND 1 & DEFAULT?
If not, how would we go about this?
Thanks.