Hi,
HikaMarket have a "sales rep" mode but the vendor attribution is made thanks to a customer address or to a (item/order) custom field. It is also possible to store the "preferred vendor" in the customer profile.
But depending if the vendor attribution should be fixed (by yourself) or selected by the customer, a little development would be required.
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.