Do I claim seperate or joint in first year of marriage if we both have dependants from prior relationships but we're single the whole year til we were married?

Do i claim taxes together or separate within first year of marriage both with children from other relationships. Married Oct13 but not commonlaw before and both of us were single with me having joint/equal custody of my 2 daughters and with her having 75% custody of her sons. So we would claim a single dependent each? Claim singly or no?