Making chain from trees contained in file/TList

I have several root files, each file has a TList containing several histograms and one tree.
I would like to make a chain from this trees, but I can not find a suitable method in the TTree documentation. All TChain methods assume the tree to be on top of the file or inside a TDirectory, which is not my case.

Is there any way I can do this?
Thanks for your help

Cheers,
Ernesto