How to assign classes for group of images in a classifier?

I'm developing a Finger knuckle print biometric system. For that I had extracted SIFT and SURF Features for the image. I am having a problem in training section.

In my database there are 4 persons. Each person have 6 sample images.

For training I used 3 samples for each person. For testing I used the entire database.

But my problem is how to group the images of a single person.??

Answer 1

[Image Analyst]

Do whatever makes sense. Maybe each person's images might be in a folder with their name or something like that.

[Sabarinathan Vadivelu]

But, grouping the samples of a person using the filename of the image is not acceptable right?