This is already possible:
// NOTE: The 'silent' flag in bit 7 (0x80) avoids showing a message on player's screen.
struct PlayerHCap // Player handicaps in 4 bytes - there is an array of these in the PLH (below)
{
byte PLID; // player's unique id
byte Flags; // bit 0: set Mass / bit 1: set TRes (e.g. Flags=3 to set both) / bit 7: silent
byte H_Mass; // 0 to 200 - added mass (kg)
byte H_TRes; // 0 to 50 - intake restriction
};