jMeter how to check all

I have jMeter suite containing several thread groups, which for their part contain several request tests.

At the end I have a SMTP sampler, which I only want to use (in fact send an email on if condition) if all of previoud tests within the threads ran well, means were successful and are showed as "green" in my view result tree.

All I could found on this is http://ift.tt/2jV1MpO resp “${JMeterThread.last_sample_ok}”

Last sample is not af any use in my case, so Im assuming this is not applicable for my case. Have anybody done something similar already and can provide any hints? Thanks