How can I apply different error bars to each data point in a series?

I need to make a graph. In this graph I need to assign different error bars to data in the same series. This figure should explain in < 1000 words.

Error bar 1 and error bar 2 need to have different values. The only way I can figure out how to do this is to make them separate series. Which makes absolutely no sense. Surely there is a way to do this? Probably a really obvious one?

I am willing to use any graphing or presentation software to do this (numbers, keynote, excel, powerpoint, openoffice, google docs, etc.)

Thanks guys.