Basic broker's fee question from a non-broker

I have a quick question for you regarding broker's fee - if an apartment is listed by one company, and a broker from another company brings a tenant to the apartment, how is the fee split out among the two brokers? My apartment (that I currently pay the rent on and want to break the lease on) is up for rent and listed by one company, and I'm wondering if it's worth it to let some broker friends of mine from other companies know about the listing (i.e., if there's an incentive for them to take people to the place). Please let me know if you have any insight on this. Thanks!