With FloXpress, unless I'm mistaken, you can only select one input and one output. On the other hand, we can be cunning (within the limits of your system to be simulated).
For example, if you have a set with 2 inputs and an output. We can draw a Y as an input, so that we have only one input. This implies that you will not be able to apply different rates to the 2 inputs, and you have to "oversize" this Y so that it is not a limiting point.