Similar co-workers

?

There are these 2 ladies that work in my area that look very similar, and I swear both of them are marketing too. I work with one of them whose name I know. The other one I have never talked to, but accidentally I started smiling and saying "hi" in the halway to the other one because I didn't realize they were 2 different people... and today I ran into one of them and said "hi" and she asked how it was going.... and I said "good..." but I didnt know what else to say because I don't know if thats the one I work with or not!!!!! I was telling Kristin earlier that before I realized that they were both two different people, I had kept thinking that some days this one person I worked with looked slightly different. I couldn't put my finger on it. Thats when it all started. I really have no idea who the other person is.