There's an option in PingPlotter that allows you to "alias" an IP address to give it a name thats easier to keep track of (more details on this here: http://www.pingman.com/kb/23
). You can use this method when creating a target list to load into PingPlotter - which should help you accomplish what you're after here.
To create the target list, just open up any text editor (notepad will work fine) and then enter the targets, followed by a space, and then the alias - one target per line. So, for example, something like this:
220.127.116.11 PingPlotter Site
Once you've got your list created, save it off as a *.lst file. You can then import this list in PingPlotter v5 by going to "File" -> "Load Target List file..."
Hopefully this helps out! If you have any questions - just let us know.