Niall Lavery's question regarding SQC charts snuck its way into the wrong thread - https://pisquare.osisoft.com/message/58026?et=watches.email.thread#58026 so I'm re-posting it here.
The PI SQC 2015 User Guide has a lot of good info on SQC charts. I believe you should be able to do what you'd like by placing your filter expression within the "Sample" tab of the SQC configuration. This uses the same syntax as performance equations, so PI Point (tag) names go in single quotes, strings go in double quotes, etc. More information can be found here.