It can be hard to get your head around how the plug-in works. Even now I still get surprised by all the cases users apply the plug-in, and the different ways they use it.
You can definitely do what you want. The plug-in executes a Groovy script that must return an array with the values to be displayed on the UI. You also have some helper variables that the plug-in tries to make available for you. One of these variables is the jenkinsProject.
If in your project you assigned a label, then programmatically you can return values based on the node label assigned to your project (or to the node object...).
Here's a very simple example.
assignedNode = jenkinsProject.getAssignedLabelString()
list = []
if (assignedNode == null) {
// do something
} else if (assignedNode.equals('abc')) {
// ...
}
return list
Here assignedNode will have the string name of the node, or null if none. If you use instead jenkinsProject.getAssignedLabel(), then you will have not a String, but a Label.
If you need further customization, the best way is to dive into the Java API, then build your Groovy script from the bottom up. Or try finding examples online (there are many for Jenkins and Groovy) and adapt them to your parameter.
Hope that helps,
Bruno