I want to achieve the same thing. I have multiple poller that aggregate temperature from multiple pollers. The reason is that we have a different vendor. I would like to get the temperature of different vendor hardware to the same graph.
Also it's very sad that this feature is not here, especially for temperature. For exemple we use SysDir on IBM servers and insight manager agent on HP, with this NPM is able to retrieve the Health and Hardware, that contains Ambiant temperature. Why not give the possibility to create a graph on this value instead of being obliged to retrieve it twice with UNDP ?