I would think it is near impossible without a local guide and ability to speak local lingo...and even then the guide will tell the hostess that you are a foreigner and you will still be charged non-local rates and given a non-local girl.
The only way I can see that may help is that you also offer (besides commissions) to get him a girl too for each day you hire him. Knowing local guys prefer local girls, then maybe he will take you to his favorite local girl places and show you off as you treat him like a good friend, not an employee.
PS: I did something similar many years ago in Vietnam where I invited a local guide to go to local hostess KTV with me. I got him a girl too. My true motive was I felt I was less likely to be cheated or harassed if I had someone there with me. As we drank many rounds of local beer, the guide told me no foreigner ever treated him like an equal by inviting to drink and be merry with the girls before...afterwards he introduced me to some really good places.
