Currently, JME is used in our development. In JME, to input a reaction with multiple molecules on reactant and product sides, you will have to input one (not two or more!) reactant and one (not two or more!) product molecule at the same time. You can do this recurseively to input multiple reactants and/or products. (1) Input a reactant molecule; (2) Click the reaction arrow, then there is a copy of the reactant molecule on the product side; (3) Modify the product molecule into the desired molecule; (4) Get smirks string for the two molecules; (5) Copy-and-paste the smirks into a parent web form, then clear the editor; (6) Repeat the above steps until finishing input of all molecules in the reaction.