Back Seat cages for aero seat posts (Cervelo)?

I have a Cervelo Dual equipped with an aero bottle and one cage on the seat tube. Dual doesn’t have cage mount on its downtube and the only thing I could find around where I live is profile back seat cages which are not meant for aero seat posts. Any suggestion on how to add one or two more cages is appreciated.

Lots of rear cage mounts that attach to the seat rails instead of the seatpost. Check xlab, Minoura, or Hydrotail

oh my bad, I should have looked more before asking, thanks
.

The Minoura bottle cage holder is by far the most cost effective solution if you’re going for seat/post mounted bottles. I use the SBH-300 dual bottle holder on my Cervelo, which is not light by any means, but very solid. Do not use the Profile Design Kage bottle cage, as it’s limited grip + the angle of the Minoura holder creates an ideal bottle launching mechanism!