Unfortunately I don’t think there’s an easy way.
As a fallback you could implement the ordering transforms manually if you needed these constraints to be programmatic. The documentation for that constraint is here: https://mc-stan.org/docs/2_18/reference-manual/ordered-vector.html and the code is here: https://github.com/stan-dev/math/blob/develop/stan/math/prim/mat/fun/ordered_constrain.hpp
You can translate that into Stan manually. It’ll be messy, but work. I guess whether or not this is good is a function of how many different constraints you need and how much you need to modify them.
This is a similar question/answer: How to specify variable parameter constraints based on other model parameters
Hope that helps!