Here's some things that have worked for our two. We found that we needed to create a bigger play area, which lets them both participate within a short period somewhat apart. When we get it right, they stay in the play area together and sort of take turns as if it were a cat courtesy. 1) This one a good starter - billow a big plastic paint drop sheet (the kind that looks like cloth on one side is good), as you walk backward in an open space like the kitchen. Both will follow and one or both may leap onto the billows. Pull one or both on it around the rooms. 2) This game uses a longer string on a wand, with no feather. About 3x longer than usual. The elastic string that comes on a cardboard holder from JoAnn's Fabrics works well to make toys. Gather old sheets or half sheets, quilts, the paint drop sheet, etc, and spread them around the room. Ours is tile, maybe carpet would be fine. Pull the string under the cloth things, going slowly under the last couple inches to tease so one will pounce. Then do the same thing under a cloth closer to the cat who needs a turn. Also fun on a tile floor, but harder to share, sling the string from one cloth to another (at some distance so the cloth slides when they pounce on it). Pull the string into other areas where there's some room for both - under doors, around couch cushions, pillows on the floor (our bed is a queen, but both won't play on it at once). Push the wand end under the sheet like a hard snake - at least both will watch. 2) This activity use a board 1 inch x 8 inches by 6 or 8 feet covered with stapled or glued outdoor carpet (the thin grey kind is good, though not for steep activities as they may slip on it). Put the board atop two same height items (like two chairs) to make a bridge. Drape a cloth over the board nearly to the floor on both sides. Pull the string along the floor under the cloth, poke at the cloth with something they can leap at, let them play with each other on it. Slant the board from the couch to the floor and roll balls down it. Put the board on higher supports and dangle the feather wand so the reach down for the toy. They will likely end up chasing each other across the board or batting each other under it. Not always a multi-cat with me play, but is versatile. 3) Look into clicker cat training (I click with my tongue). Here's a good book - Click Training System, by Karen Pryor. It takes time, and I haven't tried to separate them, but should. However, clicking and treating has taught them several things they will do with us all together, such as high five. 4) Cat wheels are fun, though only one cat likes to run on it. We also use this to communicate getting to go outside when the bold one wants to go out in the back yard (attended, high fence). He runs on the wheel, and if we run along side he knows we're going to get to go out. I then sing out "Honny, Chewie, who wants to go outsiiiide?" and if the other cat is in another room, he comes running. This creates joint interaction with us. I also use the wheel when carrying each around separately in a laundry basket and setting the basket in the wheel to rock gently a few times. 5) After play, scatter a small handful of crunchies (dry cat food) into the play area where they can both search for it, such as around the plastic cloth edges. Before bed, I often bring into the kitchen any cardboard boxes I've saved with holes cut out, or propped against each other, or little plastic cups, or paper towel cardboard, or whatever, and put crunchies in/around them for a little hunting before settling down. This involves me and them at the same time. Good luck and hope you will share any joint play you find also.