Haw. Rev. Stat. § 480-5: Requirements and output contracts; tying agreements.

No person shall sell or buy any commodity, or fix a price or discount from, or rebate upon, such price, on the condition, agreement, or understanding that the other person or persons shall not deal in the commodity of a competitor of the seller, or shall not deal with the competitor of the purchaser, as the case may be, when the effect of the sale or purchase or the condition, agreement, or understanding, may be to substantially lessen competition or tend to create a monopoly in any line of commerce in any section of the State.