I have, but when the cron runs it still sends to one server. After a minute it stops and then sends to another server. It doesn't send to all 4 at the same time.
In the latest (beta) version v1.3.7.5 as of yday my test yielded the first DS had its quota overrun and then 4 others being used in parallel (until their quota was overrun), so in a way the answer seems: yes, but I need to test more to see when they are put into parallel send mode (perhaps after the first batch is through or all processing is done).I do have v1.3.7.2 is there a setting with the latest version that will allow you to do this?