That is a really broad request. If you have specifics about costs, size of terrain, crowds, apes ski,etc.,etc., I am sure there are plenty of people here who can help you with your planning.
Two things you might want to take into consideration for that time of year are:
1.) Crowds: Early January sounds like a fairly slow time of the season. -- Please be aware there are no really slow weekends(Fri,Sat,Sun,Mon) in the I-70 corridor. If there is good snow and people can get there, you will have a lot of other people on the slopes with you. Those resorts include Breckenridge, Keystone, Copper Mtn., and Winter Park. The crowds also spill into Vail if the snow is good. They are all big mountains, but can get really congested in the base areas.
2.) Snow: Early season snow can be a challenge in any given year. The early season snow champ in Colorado could probably be considered Wolf Creek. They benefit from several weather phenomena, while others in the state might be in areas protected from some of those conditions. They also have a very high base. -- There are areas that try to help Mother Nature with the snow. Vail and Beaver Creek have tried cloud seeding in past years, and I think Durango tried it also. In a low snow year, it can make a difference. Snowmaking is utilized at most ski areas, but that will be on terrain focused toward the lower skill ranges of your group.
If you have specific questions, I am sure there are locals from most every area in the state on this site.