SPP high availability

Hi,

My question is.
Is it possible to create a cluster of 2 SPPs to use the high availability features?
In the documentation are reported solutions to 3 or more appliances.
My aim is to use a cluster of 2 SPP appliances in HA. Connected to 2 SPS already in high availability.
Are there any special instructions to follow?

Greetings

Thanks for your help