Executive Summary: Have more hosts take turns, round robin-ish, at long enough intervals to stay under the radar, guessing for weak passwords.
The plan is much like before, but now we have more host on the attacking side, so
Pick a host from our pool, assign a user name and password (from list, dictionary or pool)
For each host,
Try logging in to the chosen target with the assigned user name and password
If successful, report back to base (we theorize); else wait for instructions (again we speculate)
Go to 1.
For each success at 2.2, PROFIT!