There are many different options out there for mixing your Boxcast video. The below options cover only a small fraction of them. Feel free to make a choice that suits your broadcast needs. Note that we will certainly attempt to help you if you run into issues when implementing a mixer but your best bet will always be to contact the actual product manufacturer themselves as they will have a far better idea of the limitations of their product.
Wirecast ($495) - good on all platforms
BoinxTV ($499) - Mac only
VMix (Free - $1200) - PC ONLY
Roland V-1HD - ($995) Highly portable unit with enough features to satisfy a standard broadcaster.
BlackMagic ATEM ($995 - $1600) More of a rack mounted system but great bang for the buck.
Tricaster (~$6,000) The cadillac of mixing equipment. High end quality and features.