@MacL3an a bit further down in the thread Pablo mentioned there are some suggestions on how to possibly use annotations to encode the kind of conditions you wish to have, see Agreeing on optional user interface hints in templates - #19 by erik.sundvall The annotations can then be transformed into other formalisms, (including into vendor specific form rules/actoins)
At Karolinska University hospital in some multi vendor use-cases we have the same need as you described, and we don’t want to reimplement the same things over again in each vendor’s own form editor etc. We’d prefer to automate at least some of that based on e.g. annotations in templates. Since we need it fairly soon we’d prefer to start by using annotation features of existing template editors rather than first inventing a specific language, new tooling etc.