WORKAROUND:
1.- Create workflow to create/update users in target domain.
2.- Use Powershell script in the "Step Handlers" section using it "After committing step run results". See script sample below:
Import-module ActiveDirectory
$username = "DomainName\administrator"
$password = ConvertTo-SecureString -String "password" -AsPlainText -Force
$cred = new-object -typename System.Management.Automation.PSCredential -argumentlist $username, $password
$users =(Get-ADUser -Filter * -SearchBase 'DC=DomainName,DC=com' -Properties extensionAttribute1, samaccountname)
Foreach ($user in $users)
{
$extensionAttribute1=$user.extensionAttribute1
$samaccountname=$user.samaccountname
if ($extensionAttribute1="Group1")
{
Add-ADGroupMember -Identity Group1 -Member $samaccountname -Credential $cred
}
else
{
Add-ADGroupMember -Identity Group2 -Member $samaccountname -Credential $cred
}
}