[rules-users] Testing for global variable

Is there a way to test for the existence of a global variable in a StatelessKnowledgeSession before inserting a SetGlobal command into a BatchExecutionCommand? I am trying to write a rules executor class that may execute some rulesets that need a particular global variable and some that don't. So I would like to be able to automatically test whether the rules that I am about to execute have the global variable and if they do not then not to insert the SetGlobal into the batch. I am using DRools 5.1 Chris Selwyn