Performing actions when conditions are met in Grasshopper?

Question

3D

Good afternoon for everyone! Recently got into parametric modeling, and created a prototype of a small table that lines up on its own when you set the overall dimensions. But I decided to complicate the task a little - add additional supports, provided that the length of the table exceeds a certain size. The logic is this - if one of the dimensions is larger, for example 1500mm, a support is added in the middle between the extreme supports. Decided to use boolean. The operator is as follows: input conditions - the received value and the value with which the received value is compared, at the output: if more - true, if less - false. That is, at the output we get 0 or 1. And what to do next with this? All values ​​are there, condition checks are there, but grasshopper does not have operators for creating objects when conditions are met. You can create, for example, normal BOX for two points in space - input data: point 1 and point 2. That's it! Helb!