How can I make a random level selection system in my game? (Batch)

What I thought up:

:TransL
cls
set num=%random% %%5
if %num% == 1 goto Level1
if %num% == 2 goto Level2
if %num% == 3 goto Level3
if %num% == 4 goto Level4
if %num% == 5 goto Level5

How can I reset it every time I goto TransL so a new random level will select instead of it going to the same level over and over again>?