Multi variable fit

Hi,

Need help with fiitting user defined function to multidetector data.
Beside x, function has six more variables which are different for each detector and I want simultaneous fit to many detector data using the same function.
Ideal fit line should pass through all the data points.

Best Regards
Hardev

http://root.cern.ch/root/html/tutorials/fit
http://root.cern.ch/drupal/content/numerical-minimization#multidim_minim
grep -r Minimize ${ROOTSYS}/tutorials