How to create different tokens from three different result fields depending on if an option is null?

I would like to create a token from result fields for meeting dates in different seasons (Autumn, Winter, and Summer). I've created an if function where if the date is more than 30 days from the today, it will display the original date, otherwise it will show NULL. This way past meeting dates will be removed, and future ones will stay. Now I want to create a token that can extract the date from the new eval fields on the condition that it is not NULL. I.e. if it has data, it will extract it, if not it will move on to the next one, if null it will go onto the next one etc. The aim is to be able to extract the result and put the token into a block of text I have in HTML. Can anyone help?