Have a "custom chip" that allows us to design a circuit to put in the chip, then, show the chip as an IC in our main circuit. If we click on the chip like we are going to change the settings it shows our sub-circuit that is in the chip so we can edit it. Include a back arrow on the sub-circuit for when we want to go back to the main circuit. You can limit which components we can put in the custom chip if it gets too complex to do the simulation. For example, no switches inside the chip.