Who Does What When Report Not working

I am currently working on a project where I am responsible for maintaining 30 plus project schedules that are to be rolled up and reported to upper managment. Reports that they would like to see are what a resource is doing and where we have resource holes that need to be filled (resource allocation type report). We do not have Microsoft Project Server. We currently do not know if getting Microsoft Project Server is feasible because our project team crosses 3 different contract companies as well as the governement. (I was told that you need to have one Exchange server to support the software functionality and this causes a problem with the firewall rules in place for the government and various contractors). I also don't know if Exchange server would resolve our reporting issue. (See below)

I have tried to use the who does what when report, however, I do not see a way to view all of the details of this report unless all projects are open. I have to have all projects open because my resources can be on multiple projects. The problem is that Microsoft Project crashes after opening more than 15 projects.

My detailed question: Will getting Microsoft Project Server allow me to generate the allocation report without having to open up all projects? Is there another solution out there for me incase I can not stand up a Microsoft Project Server? If the only solution is to stand up Microsoft Project Server I need to know this so that I can encourage management to invest in the time to resolve our integration/cross location issues.

Thanks in advance