For anybody interested, we managed to do this using the script below. Thanks.
function getParticipant() {
var workflowData = workItem.getWorkflowData();
var path = workflowData.getPayload().toString();
log.info(path);
var node = workflowSession.getSession().getNode(path);
var tagValues = node.getNode("jcr:content").getNode("metadata").getProperty("cq:tags").getValues();
for (var i=0 ; i < tagValues.length; i++) {
if(tagValues[i] == "global:test/testing") {
return "Product Marketing";
}else{
return "Technical";
}
}
return "Product Marketing";
}