Override the 1040-V payment voucher for 1/2 the amount. Either give both a copy and envelope or give it to one of them and use elect funds withdrawal for the other 1/2 amount.
For Electronic Funds Withdrawal with the tax return you can only list one bank account. The only way around it may be to do a partial withdrawal with the tax return from one account and then make the other payment on the IRS/State web site.
**Say "Thanks" by clicking the thumb icon in a post **Mark the post that answers your question by clicking on "Accept as solution"
Can you file them MFS? If not, the above may be a solution, as long as the other payment is made, but how will you know? Make sure you have those Conflict of Interests on file 🙂
