rootId = roots.iterator().next();
} else {
rootId = System
.getProperty("org.apache.ctakes.ytex.defaultRootId",
DEFAULT_ROOT_ID);
ConcRel crRoot = cg.addConcept(rootId);
for (String crChildId : roots) {
ConcRel crChild = cg.getConceptMap().get(crChildId);
crRoot.getChildren().add(crChild);
crChild.getParents().add(crRoot);
}