How to set a value to some of the coefficients in glmfit

Hello,

I want to use GLM to model the binary data. I have 3 different covariates, X1, X2 and X3. X1 is estimated with 14 basis functions and X2 and X3 are estimated with 10 basis functions. Hence I have 14+10+10=34 basis functions. When I run GLM I will get 35 coefficients (one extra is for the constant term). I want to be able to give an initial value to some of these coefficient and not allow GLM to change it, that is, I want GLM to estimate the remaining coefficients. Is there anyway to do this with glmfit or some other functions?