This custom tool allows you to enter a comma separated list of users to add to a group.    The vbs script will need to be modified for your environment.   You need to edit the name of the DRA server in the script and the name of the domain it searches for the users to add to the group.    In addition the client machine where this is being run will need the DRA ADSI provider to be installed.   If multiple domain is needed, the script could be altered to search "All managed domains"

The lines that will need to be modified in the script are:

const EASrv="\\secadmin10"

vsInput.put "Container", "OnePoint://DC=Secure,DC=local"

BTW:  if you wanted it to search all managed domains instead of a single domain for the user tot add to the group, you would change the container to

vsInput.put "Container", "OnePoint://module=Accounts"

However this will work if the samaccountname is unique across multiple domains.