When I run the script I've written for 100 or more threads, our app tends to start failing. Although, the error we're getting are application generated errors, meaning, we get a customized error screen. Now, ideally we should have the developer also return a different HTTP status code other than 200, but at this moment, that's not going to happen. So, I'm wondering if there is a way within JMeter to modify my script and look search the result for a speficic string, and mark that as an error?
Currently, I'm using the Aggregrate Graph and comparing the number of times the script has hit a page. This isn't neccessarily an accurate count because some of the successful results are really errors, they just happened to return a 200 status code.

