Using SCOM Command Shell(PowerShell) to Configure Agent Failover Between Multiple Gateway Servers
If you need to deployed multiple Gateway servers into a domain that does not have a trust relationship established with the domain that the rest of the Management Group is in, You can configure agents to utilize those Gateway servers for failover. But you have to use the SCOM command shell to do this.
Here is an example:
$PrimaryMS = Get-ManagementServer | Where { Your Filter Here}
$FailoverMS = Get-ManagementServer | Where { Your Filter Here}
$Agent = Get-Agent | where {Your Filter Here}
Set-ManagementServer -AgentManagedComputer: $Agent -ManagementServer: $PrimaryMS -FailoverServer: $FailoverMS