Calculating on hold time within a project

I like this idea. We have many projects on hold but when they become active again there is no way to tell how long they were held up.

This is a critical factor for us. Projects go on hold due to client resource constraints or a number of other reasons and we have to track our cycle time (time PM is engaged on a project) from start to finish minus time on hold. Haven't been able to create a report that takes into account the time the project status was On Hold.

I need this same concept except instead of "on hold", I need it for a custom project status. We need to know the total duration of time a project was in this status over the course of the project.