Don't forget that in this game, you are in control. The mechanics and integration on your side are just as important as that of the agencies you hire. Consider the people on your end who will manage projects and make them run smoothly. It is extremely important that you hire the right people for your team.

Believe it or not, your internal team can play a large part in eliminating turf wars between agencies. I know of one well-known Fortune 500 company that makes the experience of managing multiple vendors part of the hiring criteria for new employees. Hiring employees that are good at managing vendors can be as critical as anything else because agencies don’t typically want to work together. They want all of your business. Don’t forget-- it’s about the bottom line for them, too.

And don’t be afraid to take the same principle and apply it to your reference check on each agency. When you call former or current clients for insight into the agency, ask if the agency worked with other agencies on projects. Some other questions to ask:

• How did the projects go? Were they seamless and easy?
• Did they play well together?
• Was there a blame game or problems with one trying to take all the credit?
• Were deadlines met or affected?
• What kind of things held up projects or caused delays?

In addition, ask to see an integrated project that they did work on together. Often they will all say how they are good to work with, but it’s about what is produced. There's a chance that they could have been great to work with, but no one was driving the project forward so their projects just fizzled and everyone got paid. That’s a great working relationship-- for the agencies.