Copy the text below into Notepad to create a batch file to open and run multiple ZoomSearch configuration files consecutively. It's pretty useful if you have more than one build in RoboHelp project and they all have different .zcfg files:

zoomindexer.exe -o firstfile.zcfg
zoomindexer.exe -o secondfile.zcfg
zoomindexer.exe -o thirdfile.zcfg
ECHO OFF
ECHO Indexing complete!
PAUSE
EXIT

Be sure to save it as ".bat" NOT ".txt".

This file will automatically open Zoomsearch, load the specified configuration file (firstfile, secondfile, thirdfile, etc), run the indexer on the folder associated with the configuration file, then close ZoomSearch.  Everything is displayed in the command window.  I added the "Indexing Complete!" for a little visual confirmation if everything works correctly. The "PAUSE" command will force you to press a key to close the command window. Otherwise, the window would close automatically. 

I've built a batch file for 3 different configuration files, but I don't think there would be a limit on the number of .zcfg files you could string together, as long as you put each one on a separate line with the correct parameters.

This batch file must be stored in the C:\Program Files\Zoom Search Engine 5.1\ directory and ALL of the configuration files must also be in this same directory.  For convenience, make a shortcut to the batch file and it on your Desktop.

For more information about ZoomSearch command line options, see 

http://www.wrensoft.com/zoom/support/faq_commandline.html