How do I keep layers when moving rhino pdf into illustrator?

Whenever I save a pdf from rhino and then try to open it in illustrator, all my layers show up under “Layer 1”. Does anyone know if there is a way to keep the layers? I have tried exporting directly from rhino but it tells me that I do not have permission.

Hello- if exporting to Rhino’s old AI format works,I would use that.