NO ... unless you like paying taxes on the income twice you will NOT import the account to both accounts. If you have joint accounts then you must divide the income from the joint account between the 2 returns as you agree to do. And if one of you itemizes deductions the other MUST also itemize deductions even it they have none to list on the Sch A.
you have two issues as Critter 3 said you can not import. you must manually input the info splitting according to whatever you agreed to unless you live in a community property state. Then it's probably 50/50. The other issue you face is that there is probably only one SSN associated with each account. so when the IRS goes to compare what each of you reports on your respective returns to what's reported by the broker(s) under each SSN there's likely to be a difference. so the IRS is likely to send each of you a notice about the discrepancies.