How to distinguish between classes with the same unique identifier in a class diagram? -

can primary key inbox_id in userinbox foreign key employerinformation , userinformation?

context:

users , employers can send feedback administrator's inbox. feedback stored in table userinbox. (image shown below)

issue:

both userinformation , employerinformation have record_id unique identifier- i'm not sure if can use identifier (message_id) connect userinformation , employerinformation userinbox hard distinguish between 2 record_ids.

it's not idea make inbox_id foreign key in userinfomation , employerinformation, because 1 user may have numbers of feedbacks, user information duplicated many times.

one approach problem using idea of inheritance, meaning both userinformation , employerinformation inherit user table, , user table keeps common information of userinformation , employerinformation record_id , img_id. userinbox table keep record_id foreign key.

userinformation ------ user ----- employerinformation                         |                      userinbox