Transfer iMovie projects to another storage area

I am accumulating a number of iMovie projects and events on my primary drive that I want to move to a storage hard drive. Four projects are occupying 18 GB of space and also taking up space in Time Machine.

The projects have been finalized then converted to QuickTime movies and used in iDVD but I want to keep the original material in case it needs to be modified in the future.

I have experimented by duplicating a test project and moving it to another drive (within iMovie) where iMovie created a new project folder. I was able to move it back again (within iMovie).

Can the .rcproject files be moved to another location (other than an iMovie project folder) on another drive so not be seen and loaded by iMovie, as many projects can really slow down loading and response of iMovie as the number of projects it reads becomes greater? I understand that iMovie has in the past kept a kind of pointer file to keep track of all the data within a project. If I just store an .rcproject file like ordinary data, can moving it back into a iMovie project folder work and not loose pointers?