Hi,
This is a process of several steps. You can start by augmenting the markup, ie. add an input element and a label to search for groups. It's done in the *ftl file.
Then you can alter the behavior of client-side javascript, which will:
- hide the person finder and unhide the group finder input element
- when user searches for a group, do a call to backend, it is similar to the people search, just slightly different param. Check this in group-finder.js file.
- when you get back this group and select it, do another ajax call to backend to get all people in this group, and put these as a data source for input element, and unhide the people search element now.
This would be done in client side component, somewhere in /share/components/people-finder/people-finder.js
Try looking at those files and ask for help once you figure out your next question.