Hello,
HikaMarket has a "vendor selector" feature to dynamically assign a product to a vendor depending an item custom field or an order custom field.
There is no plugin to dynamically assign depending the category ; a product can have multiple categories so it would be very complicated. We prefer to advice the assignation via mass-action in such kind of setup.
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.