Propagate bin boundaries to RooFormulaVar of RooHistFunc


I want to construct a complicated formula of a set of RooHistFuncs, but I want the binBoundaries to propagate correctly. I have found if I make a RooFormulaVar from a set of RooHistFuncs, then result is not “isBinnedDistribution” and has no “binBoundaries”. Is there a way to make my RooFormulaVar appear to be binned?