How to: Iterate a field collection when constructing a rule.

I'm trying to write a rule that will send an email to users of a role. Within the body of the email, I'd like to display the contents of a nested field collection. I've tried using what rules gives me for data selectors, but, I can't seem to put it together. Specifically, I have two field collections: field-boat-lineup and field-equip-rowers. 'field-equip-rowers' is actually nested within 'field-boat-lineup'. The contents of 'field-boat-lineup' are consistent. That is, their fields are fixed values except for 'field-equip-rowers'. 'field-equip-rowers' is variable and can consist of up to 8 user names.

Can someone point me in the direction of how to display the contents of the field collections in the body of an email? Do I need to write some PHP code to make this happen? If so, what's the critical piece I'm missing?

On a side note, I find the field collection syntax used when working with the rules data selector somewhat confusing. Specifically, the use of what appears to be an index. For example,

[node:field-boat-lineup:0:field-equip-boat-name:title]

I see the usage of a '0','1', '2', and '3' in the above token. I'm never quite sure what to select: 0, 1, 2, or, 3. Can anyone shed some light on the purpose of the numbers?

Any help would be greatly appreciated.