A way of using existing arpa LM in interpolation

[tomassykora]

Hello, I'd like to use arpa format LM as input into the interpolate binary. It's probably not possible to do directly. But isn't there any workaround, e.g. reformatting the arpa format into the intermediate format or something similar? This is all due to an experiment I'd like to try. I want to take several n-gram models and interpolate them into a single one using a certain tuning set. Then I want to take this interpolated n-gram and combine it with another n-gram (not from the initial set of LMs) in a second interpolation round while using a different tuning set.