I have a model with the continous variable(Y) that takes zero values. So, I am trying to use the limited dependent variable model (Two part/Heckman) , but I have binary endogeneous variables (two) ($X_1$ and $X_2$) also which I think are jointly determined. I am guessing now I have three probit (including probit part of the heckman(Two part). So, this is the trivaariate probit model. Am I in the right path? or is there any standard modelling procedure to handle this issue.