In my specific case, I sent all my payments through my sister-in-law who acted as pay master. She did a great job especially when I implemented the pay for performance measures that made payments variable based on performance.

I would suggest that one good well-established way to send money to the Philippines is https://www.xoom.com.

If you can't find a pay master, you can send payments directly to the interns parents. If they have a bank account, payments can go in fairly quickly.

I know in my case, having family run the intership finances made it easier than it might be for just an average person on the street. I think there is value in building up  trust and slowly growing some pay master type contacts that  help you administer your internship program. Maybe you could start with my sister-in-law! She still has 2 kids in the university where I ran the internship who could get payments to interns.