You can make a separate client and server scripts that dont match.
Quote from the manual about session_open:
A8.10 When the name begins with a '*' character, the session is unprotected. Unprotected sessions can be joined by any client, even with a different script. Protected sessions only accept clients with identical script. Script variable synchronization (send_var, send_string) or directly sending function or object pointers only works in protected sessions. In unprotected sessions, all variables and objects must be sent through send_data.
You will have to use send_data and prepare your data by hand (no send_var or skill...
) , but you will separate the client and server applications.