Run custom shaders before post processing stack?

I am using Unity's post processing stack v.2 as well as my own shaders that I run through OnRenderImage(). At the moment, the custom shaders are ran after the post processing stack. Is there any way to change the rendering order of these two?

 

Normally the post processing order is determined by the order of the components on the camera, at least for effects that rely on the OnRenderImage function. However the post processing stack does not use OnRenderImage and instead uses command buffers. If you want to control the order of your effect to be before the post processing stack, you’ll likely want to implement your effect as a custom effect for the post processing stack.
https://github.com/Unity-Technologies/PostProcessing/wiki/Writing-Custom-Effects