I don't think there is such feature; this site only lets you play a variant. However, you can make private games, so you could simply simulate a game up to the point you need to check, and then cancel it after checking what is needed. However, the site rules forbid making more than one account per person, so it would require to either ask the mods for permission of making some accounts only for this purpose (in the Mod Forum I guess), or simply working with several people and asking them to use their accounts. Of course, after all, the rules are for the people, so I think that the mods won't be against it. And of course, I am aware, that it would be time-consuming.

However, there are some open-source adjudicators (or you could code your own; I once did and it was super-fun for me) that could be used for literally any variant that you provide them (though each of it, uses its own syntax, but I think that AI could translate one syntax to another with no effort) and since you can check a variant code for this site (there is this button in variant view), I think this won't be much work to be done.