Your US Citizen spouse must sponsor each child separately since they do not gain derivative status from your case. This assumes that the children were under 18 at the time of the marriage. In most cases they will need to be sponsored while they are outside of the US and will not be permitted to come the US beforehand. The US Citizen Sponsor will also need to show the ability to support all members of the family. If you have more questions or wish to discuss your case in more detail, you should consider meeting with an experienced immigration lawyer.