Read only field in custom form according to role based


I am using SuiteCRM 7.2.2MAX. I have created a custom module named Dispatch which has the following fields:

  1. Name
  2. Contact Number
  3. Address
  4. Dispatch Date
  5. Dispatched Item
  6. Status

For this module i want to implement below mentioned functionality.

I have created two user groups. Group A will verify address, if required can update any field mentioned above. Now I want Group B to be only able to update dispatch date and status fields.

Please suggest me the way to implement this functionality.