You able to take them all as your girlfriend without any consequences
I'm not sure if that's a question or not but I'll try to answer it :P
The game has 4 Main Girls, and some other characters that are important to the story. You will be able to have a deeper relationship with them.
The game has lots of Side Characters. There will, at some point, exist sexual interactions with most if not all of them, but most likely the MC won't have a deeper relationship with these side characters.