Prevent particles from intersecting with a mesh used as a container I am new to Blender 3D and am trying to model a garden stone pavement using a particle system.

What I desire to achieve and what I already did are attached below. 





I need to limit the outer volume of the stones so they stay inside the base mesh. As it is unnatural that some parts of the stones be cut by other bounding meshes.
Particles are probably not gonna cut it alone, I'm afraid. I'd go with a rigid body simulation to make it work.

Add a temporary mesh roughly shaped as the final distribution of the stones, but add it some walls to confine falling stones as below.



Turn you stones placed above said object into Rigid Body Active, and the container as Rigid Body Passive.



Adjust details as necessary, in the end remove or hide the container mesh.