Hi,
Using HikaMarket, you can create one payment method for each vendor.
At this moment, when you use the feature to limit the number of vendor in the cart, you will be sure that the customer will buy only product of one vendor at the time.
Because you can do only one payment at the time, you can just use paypal on "one shot" to pay one single account (except if you use "paypal adaptive").
We are working on an improvement of the paypal plugin included in HikaMarket to have a "multivendor paypal classic" where the targeted email will be dynamic, using the "paypal email" stored in the HikaMarket vendor account.
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.