Yeah, they are a backer group with mabe a few in-house guys. But basically they provide haircut capital and software, office space, etc to CBOE market makers and I assume CBOT and CME as well.
Very, very solid group. Have worked with them in the past and they provide top quality service with decent commissions. Their role is simply to open relationships to some of the clearing houses that don't typically take small accounts (less than 5 million or so). You can open up an account with Cassandra for 100k I believe and then clear through Goldman or Penson. You can pick your own front end although they have a few that they recommend and then direct your orders straight to the exchanges.