What version of Premiere Elements and on what computer operating system is it running?
Could you post a screenshot of the trimming lines that you describe as annoying?
Also, not sure what you mean by "bring the clips back together?
You have several cropped images on the screen at the same time and you want to present
them in column/row without black borders, and you want to smooth out the interface between clips in this scheme?
We will be watching for further details.