public Set<FGVertex> getExitPoints() {
		HashSet<FGVertex> result = new LinkedHashSet<>();
		for (FGVertex vertex : getVertices()) {
			if (vertex.getVertexType().isExit()) {
				result.add(vertex);
			}
			else if (vertex.getVertexType() == FGVertexType.GROUP) {
				if (groupContainsExit((GroupedFunctionGraphVertex) vertex)) {
					result.add(vertex);
				}
			}
		}
		return result;
	}
Any time a vertex is grouped we want to make sure that any previous group affiliations
are removed.

@param groupVertices the new grouping of vertices
Ghidra/Features/FunctionGraph/src/main/java/ghidra/app/plugin/core/functiongraph/graph/FunctionGraph.java