Even though Friends account (for staff) and Student account are both using the G Suite for Education service, they are on different domains - "@friends.eduhk.hk" (Friends account for staff) and "@s.eduhk.hk" (for students/staff). You CANNOT share file directly on Google drive using the organization option like "On - The Education University of Hong Kong" or "On - Anyone at The Education University of Hong Kong with the link" from Friends account to Student account and vice versa.
The image illustrate the Google drive sharing option.

How to share?

To share file/folder to accounts on different domain, please follow the steps below:
(This example will share a folder from the "Friends" domain account to a students domain account)

  1. Login Google drive with the account you are going to share the file (i.e. kwcheng@friends.eduhk.hk).
  2. From the folder path (on the top), click on the folder name and choose "Share..." or right click the folder name on the left panel and choose "Share...".
    The image illustrate how to choose the share option on the.

  3. Enter the full email address of people you want to share the folder with (i.e. kwcheng@s.eduhk.hk)
    The image illustrate how to add people in the sharing session.

  4. Then you can choose the permission such as "View only" or allow "Organize, add & edit".
    The image illustrate how to select permission.

  5. You can add a note. Then click "Send". The system will send a email notification to the people you added with a link to access the share folder.
  6. You will find a alert message saying that you are sharing to people not in the same organization. Click "Yes" to continue.
    The image illustrate the alert message.

  7. Then the recipient can access the shared folder by clicking the email link. Or login Google drive and go to "Shared with me" on the left panel
    The image illustrate how to access the shared with me option.

You can access the share permission later on to modify the people list from the "Advanced" option.
The image illustrate how to access the advanced share option.

Note: Please avoid to use the option"On - Anyone with the link", which is not secure. Anyone with the link can access the file/link.