Thank you @spinkney. appreciate your suggestion. I will work on it little bit more and if there is any more progress, I will post here.
On another note, I ultimately like to use copula to address endogeneity in regression model. Here is a thread https://discourse.mc-stan.org/t/using-copula-to-account-for-endogeneity-in-regression/31554 are you able to assist just with some simple guidance? Thanks very much!