Multiple generic contaminants in EnergyPlus

[phy6phs]

I was wondering if you know if there are any plans to make it possible in future versions of EnergyPlus to model more than one generic contaminant? The reason I ask is we have wanted for a long time to be able to simulate both indoor and outdoor air pollutants as well as other pollutants such as Radon and VOCs at the same time (rather than having to run two or more simulations). If this is not something that is planned as an update in the near term, how easy do you think it would be to modify the code such that multiple generic contaminants could be modelled (note I've not written any C++ for quite some time)?

Many thanks,
Phil