Is it possible to add conditional logic into payment integration to show values base on selection.

Is it also possible to use conditional logic with the payment integration so that only payment options relevant to the chosen event are made available (e.g. age related price structure, race distance related price structure?).

That is possible. Here's how to apply that to your form.

1. Add a radio or checkbox to make a selection.
2. Add a condition logic to hide and show fields base on the selected option
3. Add form calculation widget
4. Add your payment option then apply the 'How-to-pass-a-calculation-to-a-payment-field'
5. Select the 'Update a form field value' condition.

6. Make sure to add Calculation Values to your radio or checkbox options so that there's a value to be passed on to your payment field.

Here's how my conditions looks like.

You can test the form here http://form.jotformpro.com/form/42334054866961.