You cannot append RTF files together with ODS, as described in this Tech Support FAQ:
http://support.sas.com/faq/040/FAQ04002.html
I would either create them this way:[pre]
ods rtf file='allparts.rtf';
** code for part1;
** code for part2;
** code for part3;
ods rtf close;
[/pre]
Or create the separate RTF files and join them together in Word. You could probably automate this with a VB script. (bringing them together)
With HTML, you can append a new HTML file to an existing HTML file, but that technique does not work for RTF and PDF. That technique (for HTML) is described here:
http://support.sas.com/faq/036/FAQ03610.html
Good luck!
cynthia