Inject inline adsense adverts in Directory plugin


We've read your very useful article at:

and we are considering using the Directory plug-in to create a geographical business directory.
The directory will have a number of sub-categories. Initially we would like to inject adsense adverts into the listings display so that they appear similar to a listing (i.e. within a dr_listing div) throughout different category levels at random positions. Do you have any suggestions how best we can do this, either using one of your plugins, bespoke code or 3rd party plugins?