The section for CCS: why bss rodata neardata should be grouped

Hi TI Engineer

       My CCS Version is CCS5.2  , complier version C6000 V7.4.1.

       When I build a program,it give a large number of  warning which I can't understand.Someone tell me to change the .cmd like this:

     group{

  bss;

neardata;

rodata;

}     Then it works.Can you tell me what does this mean?Why these 3 section must be put together?  

       And more important, is there any similar restriction in the section of the CCS program? Thank you very much, looking for your reply.