Yes, this is possible. I suggest using a small plugin for this purpose.
Create a plugin with any name and put it below mine. Paste this:
/*:
* @target MZ
*/
(function() {
const _menuPortrait = Game_Actor.prototype.menuPortrait;
Game_Actor.prototype.menuPortrait = function() {
if (this.name() == 'Reid' && this.isEquipped($dataArmors[1])) {
return 'Reid_LiteArmor';
}
if (this.name() == 'Reid' && this.isEquipped($dataArmors[2])) {
return 'Reid_HeavyArmor';
}
// use default portrait
return _menuPortrait.call(this);
}
})();