This feature is not supported in jBPM 4 yet. Could you open a JIRA issue for this? Because now we are focusing on bug fixes. Later we could discuss about how to achieve these scenarios.
Thank you very much.
when creating new issue for this scenario please link following issue to it as well: https://jira.jboss.org/browse/JBPM-2868
it refers to quite similar case it is just describing smaller scope.
I rough idea - we could add a method that will allow to set operand for query conditions. Either as a new method for the query interface or provide a new method for each condition where user can set what operand should be applied for given condition.