When I have an additional dataset loaded containing the greeks, how would you suggest finding the row related to the contract that I would like to trade?

Suppose I have an options chain for that date loaded (from T8 data), and I have a parallel dataset containing additional data.

1. How can I loop thru the various available contracts in the current chain loaded from T8 data? The examples that I found just suggest an option to select a given contract in the chain, given its parameters (strike, CALL/PUT, etc).
2. How can I relate each of those to the appropriate row in my aditional dataset?