How do I create a dependent field?

This may have been answered before, but I can't seem to find anything.

It's not clear how to create a dependent field in Fields Builder.  It doesn't make sense to display a 50 US States field if Canada is selected as the country.

As far as I've seen there are no dependent fields in the field builder.  I know AlexT said in one of my post there is no way to cross correlate field's within the builders, this was for matching purposes then, but I'm willing to bet the same goes for any type of correlation you are trying to create.  I'm sure it's possible to do a custom job and make a nice mod file.

Yeah... I know it doesn't exist.  Boonex avoids my sarcasic questions, that they have no good answer for. 

It's only common sense to have certain fields dependent on others.  If I want a states field, I should be able to set it so that US must be selected as a country before it appears.  If 'Match Making' is the primary reason we cannot set up a dependent field, then Boonex needs to rethink their matchmaking algorithm.  I think a properly constructed join form is more important than 'matchmaking' on someone's nazi-transvestite-biker site.

He said that the program CANNOT cross match fields at all even though the program clearly allows you to specify the field to match your field with.  This system is in need of some major tweeking.