Multisig address with a specific required signature

Question

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?

Answer 1

redeem:

<pubkey3> OP_CHECKSIGVERIFY OP_1 <pubkey1> <pubkey2> OP_2 OP_CHECKMULTISIG

scriptSig:

OP_FALSE <sig1> <sig3> <redeem>

or

OP_FALSE <sig2> <sig3> <redeem>