Add two people into a picture

I'm in need of a skilled photo editor who can seamlessly add two individuals into a photograph beside a specified person. The finished piece should look like a group photo that was taken all at once, maintaining a high level of realism, just as if they'd been there in person. The addition should be so natural, that it would go unnoticed to those who weren't aware of the original photo.

Please ensure you have the following:
- Advanced image editing skills, particularly with adding individuals to existing photos
- Ability to maintain the original style and feel of the photo
- Attention to detail to ensure the results are as realistic as possible.

The ultimate goal is to create a convincing piece preserving a special moment with all present, even though some could not be there physically.