exporting as group doesnt work in blender?

a friend wants movable grass in a movie hes workin on, and i dont know how to have each grass blade be poseable while all being one model.

heres a pic

i thought exporting each model as a group would work but i get some weird error message.

is there a way to have movable models like this while still being one model file?

Wouldn’t it just be a ragdoll, though?

Why not join them as one object with Ctrl+J?

It’s for SFM use.

i did do that. the bones stop working when i do that though. i tried exporting as a group but i get this error message

Remake the bones when you join them together.

Are all the bones also under one armature?