Answer:
coopetition
Step-by-step explanation:
Coopetition refers to competing firms cooperating together in order to gain mutually beneficial results but they still compete with each other. Coopetition is not collusion, since first of all, it is legal and ethical, and collusion tries to alter the market forces (e.g. set a price which is not the equilibrium price) by reducing competition.
By cooperating together, the real estate firms will be able to access a large number of potential customers at a relatively low cost, but even at that property fair, they will compete against each other.