Complex sentence: Members of the Flemish Parliament elected in the Brussels-Capital Region have no right to vote on Flemish regional affairs, only on community affairs, since affairs concerning their region are governed by the Brussels Parliament.
Split into simpler sentences: Members of the Flemish Parliament who were elected in Brussels region, have no right to vote on Flemish regional affairs. They can only vote on community affairs, since affairs concerning their region are governed by the Brussels Parliament.