tfssecurity utility is asking credentials every time the command is executed

I am trying to run tfssecurity utility to add an AD group to a TFS group of each project in a collection. Let's say there are 20 projects in the collection.

I got the project names in a notepad each in a line.

When I execute the command using a for loop in command prompt, for each entry in the notepad, the command is trying to connect to TFS and is asking for credentials.

Because of this, the very purpose of doing this with lesser manual interruption is lost.

Is there a way to execute the tfssecurity /g+ for a list of values in a notepad, without asking the credentials for each and every entry in the notepad?