You can use the following macro in threshold value field: %{custom_attribute_name:default_value}. With that you can specify actual threshold value on the node itself in a custom attribute. Nodes, that do not have such attribute will use the default_value.
If you want more customization you can use %[script_name] macro that will be calling a script to calculate the threshold value.
As for disabling thresholds for particular DCIs - you can use the same macro as above and put some huge value to the custom attribute, that will never get reached. Or you can put node into maintenance - then DCIs are collected, but no events are generated.
If you want more customization you can use %[script_name] macro that will be calling a script to calculate the threshold value.
As for disabling thresholds for particular DCIs - you can use the same macro as above and put some huge value to the custom attribute, that will never get reached. Or you can put node into maintenance - then DCIs are collected, but no events are generated.