Implement PFMHT as a separate object (enum etc). PF HT is now PFMHT.SumEt(). Global SumEt is PFMET.SumEt().
Use object PFMHT implemented explicitely. PFMHT uses recoExoticaValidationHT product.
Uncomment LowPtDielectron and comment LowPtElectron. Add PFMHT_{rec,gen}Cut parameters.