Use A Shared Database
If you have some data you want to share with family members, you just need to set up a sync provder for all family members that points to the same account.

Advanced Sharing
Google Drive has an advanced option that allows you to import data from another personas Google Drive account as if it was your own.

To set this up, the person who has the database to be shared needs to go to the Google Drive web site or app and use the share option to share the database with the person who also wants to access it.

The next step is to make that database available to Lockrz. For security reasons, Google Drive only allows an app to access a file if it has been created by the app,  To make a shared file available you must open it using the Drive UI.

To do this, follow these steps.

1. Go to "Create a new Lockr"
2. Press "Import"
3. Choose "Google Drive"
4. Long press the "Next" button
5. If necessary, choose the Drive account that contains the shared file.
6. Navigate the Google Drive UI to the "Shared With Me" section.
7. Press the file that has been shared with you and press "Select"
8. You will now be returned to the Lockrz app where you can import the file as normal.

The shared file will now always be available for import. Any changes that are synced to this file will also appear in the account of the person who shared the file with you.  The files are the same, you are simply sharing it between two separate accounts.

Here is a video showing the process

Multiple users
If multiple users share the same database, they do not need to have the same sync providers so long as at least one person can act as a "bridge" between providers.

For Example:
User1 has a Dropbox Provider
User2 has a Drive Provider
User3 has both Dropbox and Drive Providers.

If user 1 makes a change, it is uploaded to Dropbox. User 2 has no access to this data and so will not see the changes.
User 3 syncs with Dropbox and gets a copy of the changes made by User1. They then sync those changes with both Drobox and Drive.
As the data is now contained in Drive, User 2 can sync the data and receive the changes.