To configure a group, visit the pair configuration for a given pair, then select a group from the dropdown menu. Notice how the title of the screen changes from "Pair configuration" to "Group configuration" and the save button label changes from "Save pair" to "Save group". This means you are now editting the group configuration instead of the pair configuration. Once you press save, you will be saving the configuration to the group. Every other pair assigned to this same group will now be using that configuration. The configuration specific to the pair you're currently editting will not be lost, you can go back to it at any time by selecting "No group" in the group dropdown menu.
Use this screen to add and remove groups. You can also assign a color to any group. Any pair assigned to a group will show up in the corresponding color. Once you've created the groups you want to use, you can begin assigning pairs to them. You can do this for each individual pair by using the pair configuration, or by using the mass apply feature to assign many pairs at once.
As of version 1.4, Zeno GUI allows you to configure overrides on multiple levels. To learn more, please visit the pair configuration.