Is it a shy thing or something? If I am walking towards a group of girls I can see them looking at me from a far off distance but about half way to each other they act like I don't exist. I know it has nothing to do with looks or the lack thereof because I have been called hot, cute, adorable, gorgeous, handsome and other sh*t.
Girls were checking you out and that's a compliment. The looking away thing is a part of playing hard to get and maybe you're out of their league or they have a guy. Next time if anyone of them in a group makes eye contact then definitely try to hold eye contact and smile. You'll know by her smile if she's single and interested or just interested. You could and should be really bold and ask for the time or directions or hey do you know what time this place closes. Women love a guy with confidence. Being she was already smiling and your asking something innocent in front of her friends they won't even suspect a thing. If she engages in this verbal exchange you have about 10 seconds to be memorable.
Yes, it could be shyness, it could be that they are seeing whether you notice them to boost their ego - who knows! who cares!
Your getting looks dude, so chill out and enjoy the attention. I would walk up to those girls, confidently, with a smile on my face and say "hello" initiate a conversation. If none respond just smile and walk on. Good Luck mate!