Extracting physiological signals to control external devices such as prosthetics is a field of research that offers great hope for patients suffering from disabilities. In this paper, a novel source signal extraction algorithm, based on the source localization method Champagne, is presented. The algorithm constructs spatial filters that not only maximizes the signal to noise ratio (SNR > 13 dB) of the source activities but also minimizes the cross-talk interference between the sources 10log((P(source of interest)/P(interference sources)) > 14 dB.