I have a photoshop lightroom-4 catalog and I need to transfer (if possible) some elements to photoshop elements-11 organizer.
One way could be to move the selected files to a new folder.
Then writing the metadata to .xmp sidecar files, and importing those files into the Organizer.
There is a big risk : if you change something in LR or the Organizer, the other software won't be aware of the changes.
My advice would be rather to 'export' those files, which makes duplicates, but you can work on those files independently from both softwares.
My advice is to not use two organizer softwares. Stick with the Lightroom Library Module. There is little benefit to using both, plus extra work, and major opportunities for confusion using both.