Merging animated objects to export as .FBX?

Hi everyone, I’m new to Blender and Unity (been using it for a few weeks) and am currently learning both to make a 3D game. The game is underwater, so I’ve been working on making seaweed that sways with the current. This kind of movement is different than something that could be obtained with regular wind effects, so I basically made the seaweed, gave it an armature, and animated it by hand with poses. It worked!

The problem is that now I want to make a cluster of swaying seaweeds to import to Unity as a 3D asset, since the seafloor will be covered in seaweed. My first attempt was to duplicate the object a few times and export it as an .FBX, but all the objects (and their armatures, and their animations) were still individual so it took an hour to import into Unity and would probably be horribly inefficient. I don’t need to be able to edit anything when it’s in Unity–I just want it to be one object, animated, no bones required. Can anyone help me?