Ok, I totally get this now. Great explanation. So, as always, a couple of questions...
1) Why is this necessary? I don't doubt you at all, just want to understand why the "beam" is necessary as opposed to just a standard joist which would normally be sufficient.
2) How many joists should I "double up"?
3) Is it necessary to pocket it into the brick? Or can I just attach it to the ledger board like the rest of the joists?