Sequential measurements and gates

Class WeightedSumGoal already provides weighted sums of measurements, but no sequential measurements in time. In principle, each measurement can decide which time evolution it needs. It should be possible to optimise a sequence of gates if there was a way of using the same propagation in several measurements and tell each of them to start at a specific time. Or would it be better to have a full pipeline (from generator to propagation) for each gate in the sequence?