I briefly scanned this topic on Reddit’s PowerShell subreddit. I’m not really sure if this will help anyone, but the first thing I thought of was to create an advanced function that could prompt for up to three different sets of credentials, each for a different domain. It’s loosely based on a function I have in my $PROFILE that I use for a second domain. It should be noted that you don’t have to use the function for different domains. It can be used for different user accounts in the same domain—that part is up to you.

Function New-TMMultiDomainCred {
    [CmdletBinding()]
    Param (
        [switch]$Domain1,
        [switch]$Domain2,
        [switch]$Domain3
    )

    Begin {
    } #End Begin

    Process {
        Switch ($PSBoundParameters) {
            {$PSBoundParameters.Keys -contains 'Domain1'} {
                $Global:Domain1Cred = Get-Credential -Credential $null
                Write-Output -Verbose 'Domain Creds for Domain1 stored in $Domain1Cred'
            }
            {$PSBoundParameters.Keys -contains 'Domain2'} {
                $Global:Domain2Cred = Get-Credential -Credential $null
                Write-Output -Verbose 'Domain Creds for Domain2 stored in $Domain2Cred'
            }
            {$PSBoundParameters.Keys -contains 'Domain3'} {
                $Global:Domain3Cred = Get-Credential -Credential $null
                Write-Output -Verbose 'Domain Creds for Domain3 stored in $Domain3Cred'
            }
            default {
                Write-Warning -Verbose 'Parameters must be provided to use this advanced function.'
            }
        }
    } #End Process
} #End Function