Is there a way to have Eclipse automatically detect and import/delete projects in workspace?

I have a Mercurial repository with a lot of projects and a lot of branches in it. Some branches do not contain some of those projects (because they branched before those projects were created) and some branches contain extra projects.

Consequently, if I do a switch from branch A to branch B, I sometimes end up with some projects "closed" because they were present in A and absent in B and some开发者_Go百科 projects not shown because they were introduced only in B.

Is there a way to make Eclipse display all of the projects that are present in a workspace directory and hide projects that are not found?