If you want to do a secondary sort, you can add 2 lines to the bookcase-printing.xsl file which is probably installed under /usr/local/share/apps/bookcase/ or somewhere similar. You can copy the installed file to $KDEHOME/share/apps/bookcase and then add something like
after the <xsl:sort at line 235 and again at line 245. That should do secondary sorting by title. I’ll see about adding a UI preference for this for the next big version.