Editing the Jacobian Matrix

[hussein Adel]

I want to add components on the 14 bus system that exists in MATPOWER. The 
problem is that inquires me to add P&Q at specific two buses. The addition of 
those P&Q has to be done at the jacobian matrix and the mismatch equations 
directly. It is so unclear for me how to add components at specific buses on 
the jacobian matrix or the mismatch equations in matpower.It seems to me like 
it is done as a whole and I cant make a change at a specific bus alone in the 
matrix.Any help is appreciated.