Give permission to update a contact information to only one user in C4C

Hello,

I would like to know how to implement in C4C the following business requirement : for each contact we have assigned a Main Employee Responsible, using the Buying center functionality.

Now we would like that only the Main Employee Responsible is allowed to update the contact's information. Other business users can read the contact, but cannot update it.

So in our example, user login generique can see contact Test 1 information, but cannot update it, only user Test Testname can update this contact information.

And in the same way, user Test Testname can read Contact Test 2 information, but cannot update this contact.

How can we do this in C4C ?

thanks for your help,

Christophe