...
A. Several ways to do this. If they all use similar resources ( memory, cores, time) and aren't dependant on each other, a bash script to submit jobs works great. Here's an example. Note that this will work for other applications ( Matlab) that can process scripts. Just make appropriate changes.
First create a file of R script filenames that you want to run. Make sure each line has a line ending. These should be in the directory where you invoke the script or have each line be the full path to the R script.
Eg. myfiles.lst
RT_SET_1.R
RT_SET_2.R
RT_SET_3.R
RT_SET_4.R
...