I need to set up certain fields to go to another field if a condition is not met

I am having all sorts of problems with the tabbing order.

I have three radio option fields. If a condition is met, I would like the tab order to include the fields now shown by the condition. If the condition is not met, I'd like the tab to move to the next option.

I have wasted way too much time trying to figure this out on my on. Any help is much appreciated.