Do you have the mode set to step? If that's not working have you tried using the fade sound container in/out action part to fade out the container first before calling it again?
Alternatively you could achieve the same thing with action parts
set random value "some random value" between 1 and 5
if value "some random value" = 1
play sound "example_1.ogg"
elseif value "some random value = 2
play sound "example_2.ogg"
...
end if
or even via Lua script...
local sndz = {
"vispath:sounds/example_1.ogg",
"vispath:sounds/example_2.ogg"
}
startSound( sndz[math.random(#sndz)] )