Is it halal to give commissions to translators for bringing Afghan patients to my clinic?

I am a dentist practicing in New Delhi, India. In my practice I have many Afghan patients also. But sometimes these patients come with translator. The translator asks for his/her commission for bringing the patient to my clinic. It ranges between 20-30% of the total amount. We usually raise our prices accordingly to adjust their commission. The patient usually don’t know about their commission. Is it halal to do the work like this or should I stop giving commissions. Please help me.