What you are looking for is not transparency but translucency. To activate it, create a physical material and in its General tab, switch on "Thin Shell" and activate the translucency tab. It's the shine-through effect you have with lamp shades, leaves or tent fabric.
Have something inside the tent you create shadows and use a shape for the light that resembles a lamp. It should be left visible, but translucency will make it look realistic enough.
HTH
Michael