Lets be completely honest. There are a lot of talented people in our business. Over time, consciously or unconsciously, some of us choose to work together.
Sometimes we are surprised by the desperate attempts to define these relationships as "professional networks," when basically it's just a matter of good, old-fashioned trust. If you have need for a bigger team, our friends are your friends, provided that they first gain your trust.
In this, we differ from bigger competitors, who give you the consultant who is the least tied up.