However, you cannot sign transactions using those standard Electrum wallets.
You need to create separate cosigner MultiSig wallets from those seed phrases and the other's master public key.
Is it possible to create another set of addresses with an existing pair of seeds?
Sorry, I didn't get the question.
If it's about the MultiSig wallet created from an existing standard wallet, then yes.
The addresses in the MultiSig wallet are completely different from the standard wallet and the keys used are derived from a different derivation path.
Now that I've mentioned it, it's worth noting to OP that he shouldn't use the master public key displayed in his standard wallets' info but the ones displayed during MultiSig wallet creation.
-edit-As mentioned in the reply above. (
hosseinimr93 beat me to it)