Well, you can just check out the particle plugin (75% off in the sale!): Particle Editor Extension in Code Plugins - UE Marketplace
But the gist of it is this:
I created a new decal component (by subclassing UDecalComponent) which holds the particle module ID that created it.
I then created a new particle module (by subclassing UAbstractParticleModule) which when updating particles looks at the components attached to its parent to find all the custom decals. It then destroys excess components or creates new ones as necessary (new decal components are attached to the module’s parent so they can be gathered again on the next update).
The custom decal holds the module ID to prevent different modules interfering with each others decals 