The concept you're describing is called a "smart contract." There isn't a second blockchain, but the transaction itself specifies conditions that must arise before the funds move.
Yes, i think a "smart-contract" would do the trick.. with the plus you could define more arbitrary parameters, to model some context that fits your need.
But the coin blockchain would at least to have a little context about the second one, the "smart contract" one.. binding/linking the transactions in the second blockchain to itself.
https://en.wikipedia.org/wiki/Smart_contract
And for a cryptocurrency-specific implementation, see http://nashx.com/HowItWorks
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