Question on live plants

Hey all,

Okay, so i have a "Dracaena fragrans", "Dracaena deremensis", "Epipremnum aureum" and "Asparagus plumosus". one of each, in each cage. (yep cham's looooove it!)

My question, I am seeing with the Dracaena plants that the cham's are having trouble gripping the leaves, is there anything i can do to help? they also have vines, and branches in there, but they keep wanting to go all the way to the top of the dracaena fragrans... last thing i need is the boy to fall.

also forgot to add the spider plants as well.

I have thought of adding small slits into some of the leaves, but i dont want to kill the plants either....

Any suggestions? I have also thought of just adding some thickish string in there for them to grab / hang on to.