Do what you have to do to get the business. The decision maker is the real buyer. Make sure that they are getting what they want. The decision maker is at a higher level, usually, and often knows more about what their organization needs. If this does not fit your situation, consider a presentation to all the players, after you have covered each person's needs individually.
Large clients have people on their payroll.
And people do the consultant selection. So, you need to get referred to people who have problems that you can solve, and uniquely. You have competence that does not exist in the large firms. I have done work for Apple, Cisco, 3Com, Palm and Silicon Graphics. The clients are buying my 30 years of industry knowledge, and some unique talents for getting to issues that others miss.