Linking contacts or deals?

Is there a facility to link contacts? We often have many contacts in a single company, related contacts like consultants, and companies that partner in a real estate deal. Do you have a way to model these relationships?

A common solution is to use a data field to include a common phrase (like "West Dominion Plaza") in the field. Then a text filter for "West Dominion" or "Plaza" ONLY lists those records. Surprisingly effective...