Service tax registration for intermediaries services

There are various methods in which they work. Ideal each method is discussed if known.

However generally , when they work as intermediaries but with an Apps between the seller of goods and buyer then they are under BAS and if for services they would be registered as aggregators.

I think they also work for commission from parties and need to take registration in Commission agent service also.

Further the goods are transferred on consignment sale basis and therefore they also need to take registration under Consignment head.