Browsing for Computer Names in Offer Remote Assistance

Some years ago I came across a hack that would allow an expert using Windows XP’s Remote Assistance to browse through a list of available computers rather than having to know the name of the PC in question. Now I cannot find any information regarding this. Is it possible? There are 3rd party apps that do this, so I know it must be.

Any assistance you may be able to offer will be appreciated.

Regards,
PDB