Hello,
A product can have only one single vendor ; that's one of the main rules of HikaMarket.
If you want to sell a bundle of formations ; then you have to create the formations for the vendors and then create your HikaShop bundle for the final product. HikaMarket will process the vendor fees depending the bundle price and the ratio of the vendor's products.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.