For example, 3-in-3 multisig wallet, the current process is sending PSBT to each cosigner in sequence.

1. Alice create a transaction and save a PSBT file
2. Alice sign the PSBT and send it to Bob
3. Bob sign the PSBT and send it to Charlie
4. Charlie the PSBT and broadcast the transaction

Is it possible that I can send the created PSBT file to all cosigners concurrently, each sign the transaction independently, then consolidate and combine them all into one file later?

Thanks!