there are some proprietary BLE APIs for some Samsung and HTC phones prior to Android4.3, but I don't know them in detail.
With the current firmware of the BLE-Shield v1.0.0 you cannot commiunicate with other Shields. I will work on a firmware supporting this during the next weeks, but I don't have a release date yet.
P,S.: You can try it yourself: http://www.mkroll.mobi/?p=1012