Combinepsbt

combinepsbt ["psbt",...]

Combine multiple partially signed Bitcoin transactions into one transaction.
Implements the Combiner role.

Arguments:
1. txs            (json array, required) A json array of base64 strings of partially signed transactions
     [
       "psbt",    (string) A base64 string of a PSBT
       ...
     ]

Result:
  "psbt"          (string) The base64-encoded partially signed transaction

Examples:
> bitcoin-cli combinepsbt ["mybase64_1", "mybase64_2", "mybase64_3"]