yes you can in the system def file here is an example in kfm screenpack.....
;Demo mode definition
[Demo Mode]
enabled = 1 ;Set to 1 to enable demo mode, 0 to disable
select.enabled = 0 ;Set to 1 to display select screen, 0 to disable
vsscreen.enabled = 0 ;Set to 1 to display versus screen, 0 to disable
title.waittime = 600 ;Time to wait at title before starting demo mode
fight.endtime = 1500 ;Time to display the fight before returning to title
fight.playbgm = 0 ;Set to 1 to enable in-fight BGM, 0 to disable
fight.bars.display = 0 ;Set to 1 to display lifebar, 0 to disable
intro.waitcycles = 1 ;Cycles to wait before intro cutscene is played again
debuginfo = 0 ;Set to 0 to hide debugging info (debug mode only)
;-------------------------------------------------------------------