I am currently using a modified or tweaked version of those scripts. What DevGib has will work with the one modification I posted. The property has to be called out correctly.
So your code would be this.
Code:
//targets henchman
var target := target(who);
if(getobjproperty(target, "master") == who.serial)
...<execute code for command here>...
else
sendsysmessage(who, "This is not your henchmen.");
endif
There are other ways to do this also but it really depends on what you are wanting these commands to do. Feel free to PM me on these boards if you need more help with this.