Hi,
I don't think it's a problem using HikaMarket for that.
The option to limit the cart to products from one vendor is called "Limit vendors in cart":
www.hikashop.com/support/documentation/1...t-configuration.html
If this setting is set the "One vendor", then yes, you can't have other products together with either A or B in the cart.
However, if you set it to "One extra vendor", then you can have your other products as products without a vendor (so they will be products of the main vendor), and then products from one vendor, either products from vendor A or products from vendor B at the same time in the cart. And thus, you could link Jacket A to vendor A, Jacket B to vendor B, and the other products to no vendor, and with that setting it will work like you need to, from what you're saying.
And also with the second solution I was talking about, if you combine the "shipping price per product" blocking system, with the warehouse system, you could have one warehouse for your other products, and one warehouse for Jacket A and Jacket B.
That way, the system could block the checkout when both Jacket A and Jacket B would be in the cart since no shipping method would be available for their warehouse, while otherwise, a shipping method would be available for Jacket A or Jacket B, and another shipping method would be available for the other products of the other warehouse.