Kirameki Gingachou Shoutengai

From Manga Abyss:

The grocery store's Mike, the fish shop's Kuro, the rice shop's Iba-chan, the soba shop's Kyuu, the yakitori shop's Sato, and the sake shop's Mamoru are childhood friends raised in the Galaxy Street's shopping center. When these six gather they are invincible, but after they entered middle school they stopped gathering!? It's an overflow of love and friendship in the lower part of town.

From Tokyopop:

In this delightful shojo romantic comedy, childhood friends Mike, Kuro, Iba, Kyuu, Sato and Mamoru - The Stellar Six - are the children of various stores located in the Galaxy Street's shopping center. When they get together, they're invincible...but, sadly, after middle school, they fell out of touch. Now they have to get to know each other again - and discover new feelings while rediscovering old ones!