Introduced in v2.0 GLAD allows you to save a session to your local computer and reload a session. A session basically stores your data state along with your settings allowing you to resume an analysis from that point of time. In the hierarchy of data files the session file is the top most and the figure below demonstrates that a selection file can hold data for many samples, but the session file can load in different selections and settings.
Thus you could save selections for different groups and bring them into or remove them from a session for your analysis.
Save a Session
To save a session click on the 
Save Session button in the top right corner of the page. Provide a filename for your session and save it to your local drive.
Load a Session
To load a session click on the 
Load Session button in the top right corner of the page. Click on 
to find the session file you would like to load in. Click the 
to load the session.