CRM Portal - Restrict portal user for limited number of attachments to be selected from CRM Portal.

Hi Experts,

I need to restrict portal user for not selecting more than 10 files from the portal using entity form. I am using OOB file attachments configuration in CRM Portal.

 I am not able to see any configuration on Entity form for restricting the number of attachments to be selected by the user.

Please suggest.

Thanks in Advance,