Since you are new to our controls I recommend that you spend some time examining our online demos
. This way you will get familiar with the chart features, possibilities and limitations. When you do this you will know where to look for an online demo of what you need to implement in your project.
As for your question - I suspect that you mean that you need to have two series. Here
is an online demo that might be of help.
the Telerik team
If you want to get updates on new releases, tips and tricks and sneak peeks at our product labs directly from the developers working on the RadControls for ASP.NET AJAX, subscribe to their blog feed