Is there a way to disable NumberBox clipHi clipLo once set?

I have a 2 numberboxes. They specify a range, numA, numB. A slider moves this range along a numberline. There’s another 2 numberboxes, limitA, limitB They specify the limit at which this window moves.

One implementation is to clipHi clipLo the numA/B. The problem becomes one of directionality. If the numberline goes from low numbers to high numbers, then any number higher than limitA is valid. So numA.clipLo( limitA ). On the other hand, if the numberline goes from high numbers to low numbers, then any number lower than limitA is valid. So numA.clipHi( limit A ). To do this requires unsetting clipLo/Hi. Is there such a method?

This is just like the EZRanger widget. I thought this would be programmatically easy to implement, but it isn’t.