Having external runtimes just means that the folders are stored outside of the Poser directory.  Ever since Version 5 we've been able to use external runtimes and to link them to Poser using the "Add Runtime" dialog box.  The folder structure is the same as the Runtimes inside Poser.

I have, at last count, 47 external runtimes, none of which is named Runtime.  They have names that tell me what is in them, like Victoria3 Characters, Victoria3 Clothing ... things like that.  I have external runtimes for my Props which are split up into category (buildings, vehicles, vegetation) and then by brokerage (Renderosity, RDNA, PoserPros and DAZ) and then by merchant.  Each of those folders is a nested Runtime.

If you have P5 or better and have the printed manual, there is a tutorial in there on how to create and link/unlink external runtimes.

Hugz from Phoenix, USA

Victoria

Remember, sometimes the dragon wins. Correction: MOST times.