Sometimes control and making it better is all you can manage.
Often plants that have problems are weak and disease or pest hit them.
Rust is a fungal disease, so in addition to removing affected plants and letting more air circulate through them, you might want to try some of the things that treat other fungal diseases in the garden. The research is yours - report back if you have any luck. (Products can include baking soda and potassium bicarbonate, spraying full-strength hydrogen peroxide, or treating with neem, but be very careful with neem).