I took outside to crawl in my father's large 20 ft. Crepe Myrtle tree many years ago. There were several Ratsnakes including a Black Ratsnake, 2 TX Ratsnakes, 2 Yellow Ratsnakes, 2 Red Ratsnakes, 2 Great Plains Ratsnakes, and a Gray Ratsnake. They did very well together.
The only problem was catching them but I developed a secret technique to catching them in the tree. Attach a hide box on a long pole, lift it up to their head, and many times they simply crawled right in.