GoldSim can be used to simulate competing reactions. For example, suppose you wanted to simulate the following reaction:
A ⇔ B
where the forward rate of reaction was kF and the reverse rate of reaction was kR.
The simulate this, you would specify a decay rate of kF for A with daughter product B, and a decay rate of kR for B with daughter product A.
For this particular example, in a closed system at equilibrium, you would find that:
[A]/[B] = kR /kF