If the number of the servers (and consequently the hostkeys) is fixed, then the correct solution is to collect them all.
If not (I do not know what "NIC teaming" is, nor I do not know how your servers are set up), then imo it's all wrong. Anyway, in that case you will have to use equally wrong solution like -hostkey=*.
See also https://winscp.net/eng/docs/faq_hostkey#automation

Hi, I'm new here and have very limited knowledge of FTP/SSH keys so I apologize in advance. I'm having a problem on a server that uses Load balancing through NIC teaming (whatever that means). The Server keys keep changing every time the connection is attempted. Per the doc below, I constantly use the ADD button to add the new key to the cache but at this point, I think I'm at 20+.

I'm trying to automate this process so I can set this up on Scheduled Tasks and not have to worry about it. Can anyone help me, or at least guide me in the direction of where/how I can see which keys/how many keys are now in my cache?

Any help would is appreciated.

https://winscp.net/eng/docs/message_security_breach