I don't think that there is something like that available during validation and I also don't think there should. This would be a side-effect, that others will most likely not expect, as the validation framework should really only do validation.

I don't know the bigger picture of your project, but to me that sounds like something that should be fixed on the client side. If your domain can only handle a certain format, clients should be rejected when trying to pass anything invalid. For me it just feels a bit wrong to simply accept everything and then silently filter out whatever is invalid, without notifying the client about it.

If you think that is not an issue, you could still do the filtering at the controller or domain layer, but it should be something very explicit and not hidden within the validation logic.