Multisig address with a specific required signature Is it possible to create a multisig address such that it has 3 public keys attached, needs 2 signatures to create a transaction, but one of the signatures must be from a specific public key of the 3? If so, how?
redeem:

&lt;pubkey3&gt; OP_CHECKSIGVERIFY OP_1 &lt;pubkey1&gt; &lt;pubkey2&gt; OP_2 OP_CHECKMULTISIG


scriptSig:

OP_FALSE &lt;sig1&gt; &lt;sig3&gt; &lt;redeem&gt;


or 

OP_FALSE &lt;sig2&gt; &lt;sig3&gt; &lt;redeem&gt;