It's seems not to be possible to share the files directly amongst multiple MATLAB mobiles. It's possible to share file using MATLAB online. So, to share the file you may consider following workaround:
1. Open MATLAB mobile.
2. Launch MATLAB online using a browser from the same mobile.
3. Create a workspace variable.
4. The variable should be automatically sent to MATLAB online workspace through MATLAB drive cloud storage in real time.
5. Now, Save the variable in a '.mat' file and put that file in a folder (say, myfolder)
6. Right click on 'myfolder' and you can see an option called 'share'.
7. Select 'share' option and it'll prompt for the email id or user id with whom the file to be shared.
Thus the file will be shared with the specific user ids.