I recommend using
&pan to zone 3 in 5
@transition fade in AND pause for 5 (changing the zone number and time to whatever you want it to be, of course). You may also want to end it with @transition fade out black if you want it to pause on the last zone while it fades out. If you want no pause but still like the look of fading out, you could use something like
&pan to zone 3 in 5
@transition fade in in 1 THEN pause for 2 THEN transition fade out black in 1