Is it possible to explicitly access a mipmap level?

Hey everyone,

I'm writing an image-based lighting (IBL) shader, and I'm using a roughness map to decide how much to blur the environment texture. For optimization's sake, I'm not blurring the texture every time, but I'm storing many progressively blurred texture layers inside a 3D texture.
This operation requires a lot of unnecessary memory since the blurred (low-passed) versions of the same texture can be represented with a smaller amount of pixels without any aliasing. Moreover, this limits the reasonable number of layers I can use. I'm basically replicating the concept of mipmapping but without reducing the dimension of the textures progressively.
So, I'm wondering if there's a way to explicitly access a specific mipmap layer inside a Jitter shader.
I know that you can sample a texture with the command

color = textureLod(textureName, coordinates, mipmapLevel);

to specify which layer to go fishing from, but I'm not sure if this works in a Jitter shader.
Thanks for your wise help!