Managing Resources across multiple projects

I am trying to solve a resource management problem and I haven’t found a solution yet.

Here’s what I’m trying to do. I want to see all of my team members and what projects they are working on each month. I have created all of the project records in a board and have set a date range for each project. I’m then able to assign multiple team members and view everything in a workload view, so far so good.

The problem comes in when I have someone assigned to multiple projects and I realize that maybe they have too much on their plate for a given month and want to begin their involvement in a project later in the month or the next month. For example

John Doe is allocated to be working on Client Project 1 and Client Project 2. Project 1 started in January and is continuing through April. Project 2 is starting if February and is set to also run through April. Although Project 2 is starting in February, John Doe is too busy to begin work on Project 2, instead I’d like him to start in March.

This is what I can’t find a way to visualize. In the workload view I can see that he is assigned to multiple projects and that he may be overloaded but if I drag the slider for Project 2 to start in March for John Doe, then it changes for everyone.

I hope this makes sense and I hope someone out there as a suggestion.