ssh, accept two key fingerprints for the same server IP

ssh clients (by default, at least in Ubuntu 18.04 and FreeBSD 12) always check if server's key fingerprint is in the known_hosts file. I have a host in the LAN which has dual boot; both the OSs use the same static IP. I would like to connect through ssh to **both** of them, without encountering errors. This obviously violates the checks performed on known_hosts: if I accept one fingerprint, it will be related to the host IP; when OS is switched, the fingerprint changes, while the IP is the same, and I need to manually delete it in known_hosts before being able to connect again. I would like that one fingerprint, **or** the other, is accepted when considering that IP. Is there a **client side** solution to overcome this issue? I am using OpenSSH_7.8p1, OpenSSL 1.1.1a-freebsd 20 Nov 2018 and OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n 7 Dec 2017. **Note**: I do not want "no check" over the server's fingerprint. I am just wondering if it is possible to relate two alternative fingerprints (not just one) to server's IP address.