W = aX + bY + cZ

X = dW + eY + fZ

Y = gW + hX + iZ

Z = jW + kX + lY

etc...where (a,b,c...) are coefficients of the independent variables.

However, in some cases I want to specifiy a particular value for one or more of the coeffifients:

W = aX + (0)Y + cZ

X = dW + eY + fZ

Y = gW + hX + (1)Z

Z = jW + kX + lY

Does anyone know of a method that I can use to do this? I'm not looking for software specific things, I'm just wondering if this is possible with basic multiple regression?

Thanks in advance,

Lee