Hi,
One product can just have one vendor. It's the base of HikaMarket and it won't change.
Even the fee system won't be able to support several vendors, the fees is made to split a price in two parts. So you can't have several vendors for one single product.
But !
You can split a product in several parts using options.
Each option have is own price and is own vendor, so you can configure the price distribution like that.
By having a product with one single variant, you can make a required option (so the customer can't remove the option).
In this kind of scenario, you can have a product with 3 required options, with 3 vendors and different fees.
Otherwise you can create entries in the HikaShop order table in order to create yourself some vendor subsale orders ; using the HikaShop and HikaMarket triggers like the "onAfterOrderCreate", check the order_type, check the content of the order and create manually the sub sales for the other vendors.
But I think that the solution of the product option will be easier to use.
Regards,