Can Electrum Multisig public key be used several times?

Hello,

If I create a public multisig key in electrum 2 and give it to others/public, so they can do their payments, everythings fine.
But what happens, if I have to sign the wallet, because the two people got into trouble?
After I added their keys, the wallet appears and I can sign the payment.
Is my old public key still usable for further transactions with other people? Or do I have to generate and share a new one?
If possible, how can I use my old shared key in a new transaction with two different public keys?
In the wallet are still the both public keys from the old payment, which is already done.
Can I hold my old key and exchange the other both keys to create a new Multisig Wallet with other people?
If yes, how can I do that?
I don't want to share a completly new key after every transaction.

Thanks for your answers!