The six London-based individuals were produced before the Westminster Magistrates Court last week and no pleas were entered.
Magistrates deemed the offences so serious that they sent the case for trial to Southwark Crown Court in southeast London.
The four Indians involved in the case are: Aleemuddin Mohammed, 34, a supermarket manager from Harrow; Shamina Yousuf, 32, a secretary from Edgware; Shanaz Begum, 56, a shopworker from St John's Wood, and Enkata Balapovi, 56, a butcher from St John's Wood.
The two Indian-origin Ghana nationals are Shashi Kala Obhrai, 53, an optician from Northwood and Balram Kumar Obhrai, 58, a computer entrepreneur from Northwood.
The woman from Hyderabad has not been named.
A case management hearing has been scheduled for October 4 at the crown court.
A Scotland Yard spokesperson said, "The Obhrais are husband and wife and are Ghanaian nationals. Mohammed and Yousuf are ex-husband and wife and are Indian nationals. Begum and Balapovi are husband and wife and are Indian nationals. Begum is the mother of Mohammed".
The six face charges that include trafficking into the United Kingdom for exploitation, trafficking within the UK for exploitation, sexual assault on a female, and actual bodily harm.