By assigning users to various "User Groups", you can manage which users can access to which data. By doing so, users within same group would be able to reach to the data of each other, but not to the data created by users from other groups. This aspect both provides differential confidentiality and organized data structure that admin level can access to all data whereas, standard users would have limited.
To demonstrate this issue consider a Sample Form. Assume that this is a form to be filled by different users from different branches. We want the users within each branch have access to each other's data but not to other branches' data.
Say we have branches classified with respect to their locations (California, Texas). For defining groups, you have to manage your groups. After defining, you would have such a view in groups tab:
From then on, you will need to upload your excel file, which is Sample Form.xlsx in our case to SpreadsheetWEB.
The original Excel file is:
And while you are uploading it, you have to assign this application to the relevant groups and/or subgroups so that groups can access to the web based form. 
So far the application has been created, and assigned to user groups. Next, we assign users to appropriate groups. To do that, each user should be authorized for its own group from the Users and Groups Tab by using Edit icon. After clicking on Edit icon, the following screen will be displayed, and the appropriate "User Group" must be selected to place that user in that group. By doing so, a user from California can only have access to the data entered by California group's members whereas not be able to see data entered by Texas group's members. 
Once each member is assigned to their relevant group, the user assignments would be completed.
Finally, in order to have access to data within each group (without being authorized to see other data entered by other branches' members); each data entered by users must be assigned to their own group. To demonstrate, assume "caluser1" needs to assign its data to California group so that users only from California group can see caluser1's data.
First, the Data icon should be selected as follows: 
From the following screen, "New" link should be selected to adjust the status of the data created by caluser1:
After clicking on "New", the following window will be displayed. From that "Assign to Group" list, "California" must be selected, so that users within California group can access to data.
After selecting "California", the change should be saved by "Save" button and this completes the process of data access authentication with respect to different User Groups.
To check, whether another user can reach to data, assume "caluser2" signs in, and looks into "Data" tab.
Which proves that caluser2 can reach to the data entered by caluser1 simply because they both belong to the same group(California for this sample case).
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