A TTree.Project like method to fill many histograms simultan

Hi all,
I find the method Project of the TTree class very easy and very useful to make a histogram with whatever complex selection. Its potential however is reduced because for each histogram you want to make it has to loop again all over the tree. If I want to produce 100 histograms with the same selection, the program now will loop 100 times to fill all the histograms but technically it would be possible to fill them in just one loop. So my question is: is there another method of TTree class that allows to fill simultaneously more histograms or is it possible that in the future the Project method will be modified to fill more histograms in one loop for instance by accepting as parameter a vector of histograms?