Yes, you can (to a degree). Not 100% sure if this is what you’re after but in the ‘pool’ window, make sure all the audio files are checked with the blue cross in the ‘musical mode’ column (all tracks need to be set to musical mode).
Now when you adjust the tempo, all tracks will change to the desired tempo on the fly, including midi of course. I often use this technique to nail down the tempo and tempo changes during the early part of production stages. Make sure you choose the time stretch algorithm most suitable in the ‘algorithm’ column in the pool window. Together with the arrange function, its a very useful toolset.
Hope that helps