requiredIf in combination with other constraints

Using Commandbox 6.8.1+5 and cbvalidation 4.2.0-snapshot.

If I have a field, let´s say lastName that is only required if there is no businessName.
If that is the only constraint then it is easy.
But what if I also want constrain it by size or other constraint in the case that it is required?
Or optional just not required?

Does the requiredUnless, exit the constraint at that point, I don’t think so?
So how do I handle this situation, where I only need a field in certain situations but also need to do additional checks if it is indeed required, or if it is not actually required but optional and still need to check the size and or type.

I know that I can use a UDF, but is it possible to use existing constraints within a UDF, or am i back to coding each constraint myself?

lastName : {
			requiredUnless = "businessName",
                        size = "4..50"

Your best bet, with anything more complex is probably going to be a custom validator. Custom Validators - cbValidation