Defining an audio export range
If we select the option Export Selected Playback Area, as shown below, we can see that the time range being output is now modified to only include the audio within the Playback Range (defined by the yellow bar at the top of the Session).
Lastly, if we select the option "Save selected tracks as a [N] channel file", where N will be the total of the number of channels in all the selected files and one file will be saved. In the example below - there are 4 mono tracks, so a 4 Channel file will be saved. If there were 4 stereo tracks, an 8 channel file would be saved.
Note that not all DAWs would be able to use such multi-channel files.