There's two ways to do this.

You can change the interval of the savegroup, which is normally 24 hours, and decrease it to 2 hours. It will then run every 2 hours regardless.

The other option is to use the savegroup probe, with a probe interval of 2 hours, and a simple script executed as part of the probe to just return the "yes" flag to start the backup.

I'd suggest that if you definitely want to run every 2 hours, using the savegroup interval option is much simpler.

I've covered both of these options in the past on my blog. For details on using the savegroup interval options, refer to:

http://nsrd.info/blog/2009/07/09/basics-achieving-higher-frequency-backups/

For details on using savegroup probes, refer to:

http://nsrd.info/blog/2009/01/25/using-probe-based-backups-in-networker/

Cheers,

Preston de Guise.