I'm going to bring my new girlfriend on a date with me and another girl
How do you think they are going to react to this?
They're going to be a little irritated, but they will get over it in time
I do not think this is a good idea. People expect for you to only see one person if you are going on a date. It is unfair to both of the girls to do this.
The girls deserve to get used by me.
They absolutely do not deserve that from you. You need to only date one person at a time and not two. You are leading both of them on.