If you want to work with several distinct subtrees of an existing workspace, you must create a separate Eclipse project for each subtree. When performing AccuRev commands that search through all the files in a project, you can choose to include all such “sibling” projects in a single search. See Searching an Entire AccuRev Workspace in AccuRev Search/Status View.
There is an alternative to creating several projects for several workspace subtrees: use AccuRevs include/exclude facility to configure the AccuRev workspace with just the files you want. Then, create an Eclipse project using the entire workspace.