How to merge report from different build into a summarized project tab report

Based on the introduction from Include third party reports in the build results, I succeeded to view Artifact HTML in build report tab.

It's powerful but can't meet my requirement.

I want to merge the generated Artifact from different build into a summarized one in project report tab.

You can assume that I created a project, this project contains 3 builds. The 3 builds will be triggered at the same time. Each one will publish its Artifact as report to server. I need to merge 3 build's report into one summarized report and display it in project report tab.

The merge job should be done on server so I guess I need to developer a server type plugin. But I have no idea where to start. 

Any suggestion is appreciated. Thanks for your help in advance