By group instances, do you mean team instances? If so, in Chapter 2 you can get better ninja tools, like the Puppet Mask and Huge Blade of Konoha, and they provide better stats than their green colored counter parts. The color also tells you how high you can level it up. Green colored gear can be leveled up 3 times and blue colored gear can be leveled up 6 times.

Oh yeah! I remember! I get those confused a lot. Reading words and comprehending them are not something I'm good at haha. Thanks for the correction.