We're using SP 2010 as a host site for our BI system (SSRS/SSAS).

I've got several libraries

1 - Powerpivot
2 - Reporting (SSRS)
3 - Dashboards (Performance Point Dashboards)

And 1 list
4 - Performance Point Dashboard Parts

We publish report models, connections etc into folders in the Reporting Library, which has several folders within it for Reports, Report Models, Data Connections, and Report Parts.

What I haven't figured out is how to get the permissions right. Right now we're using the default configuration and those who have a requirement to author reports are put into a contributors group.

What I'd like to do is prevent one contributor from editting a report published by another contributor. And allow that contributor to be able to modify the permissions on the report they publish to grant another user the rights to edit said report.

i.e. if I wrote a report, others can read it, copy it, etc... they just can't modify my report unless I give them explicit permission to do so.

Is this possible? And if so, what is a recommended path to achieve it?