Hi,
We are currently working on a "multi-shipping" (and "multi-payment") system for HikaShop 2.2.0
With this feature, it would be possible to have new specific restriction like vendor restrictions. As soon as HikaShop 2.2 would be released, a new version of HikaMarket would be too with the integration of it.
But for the moment, the feature on HikaMarket handles just one vendor, like HikaShop handle one category restriction.
The multi-shipping mode would allow to have shipping price per vendor, so the shipping price would be impact in the vendor subsale and would be processed with the vendor products only.
If you can give us more details, it could help us because we are working on it so, it is the perfect time for such feature request.
Regards,