Parse more report for one build

[tg44]

My use-case is:
I run my unit tests, generate a coverage, rename the xml.
I run my integration tests, generate the coverage, rename the xml.
I run my unit+integration tests after each other, generate the coverage.

I want to see the unit, the integration, and the overall coverage at 3(x2) graph, and I want 3 link at the project page to the 3 generated html reports (maybe I can move the html reports dir too if needed).

I never wrote jenkins plugins but I think this is not so much modification, maybe I will try to do this myself (at the weekend), but if sb more experienced could do this, that would be better :)