Referencing Data from two files

I want to use baseline data and reference it agains new data. The question I have is if I have the baseline data in a .mat file, and the new data in a .txt file, Is there a way to reference the baseline data i.e. baseline_data.air_pressure?

Since the two files will have the same variables. I know I could import each file and name each variable, but that seem like more scripting than I would need.