Assigning user with specific owner

Assigning user with specific owner

Hi,

I'm stuck, please help ;-);

I have a module :

- Name : Sociétés
- API Name : Accounts

and two fields :

- Owner ( as owner field)
- C.S.C. (as user field)

I would like to assign specific C.S.C. when specific owner is designated.

Example : Mike is the owner so Julia and Remi are C.S.C. and if Edouard is the owner Marianne and Audrey are the C.S.C.

I think I have to use if function and get function, but I don't know how to aggregate this function.

Thanks a lot for your help !