Looking for ideas on how to achieve the following, if possible: 

I'd like to draw lines to represent favorable ring-ring stacking interactions (lines between the center of two arene rings), ring-ring edge-to-face interactions (between one atom of one ring and the center of the other ring), and between a regular atom (not part of a ring) and the center of an arene ring.

So I'm guess what I'm looking for is a way to:

1. compute the center coordinates of a ring

2. place an invisible atom there

3. create a pseudobond between this virtual atom and other atoms/virtual atoms

Any suggestions as to how I could achieve this?

Cheers,

Alexis