Cooperative purchasing, also called piggybacking, lets state and local government entities use existing contracts awarded by another government agency, like a state or a larger county, to buy goods or services.
My firm has done a few of these. You need to get on the state contract first, that is how it works. You can't just register somewhere and jump on an existing contract. My shop got a statewide term contract for janitorial services a few years back, and that opened the door for us to bid on work with smaller counties and school districts that wanted to piggyback off that state contract. Check your Florida state procurement portal for how to bid on those statewide term contracts for grounds maintenance. The NAICS code 561730 for landscaping services is a good start to find relevant bids.
State and local purchasing follows state procurement codes and the specific portal's vendor guide, not the FAR. Each state has its own rules. Once you have a state contract, the local agency reaches out to you directly or posts a notice that they intend to use that contract. It saves them time and money because they don't have to run their own full solicitation process. It's a good way to expand your reach once you get that first big win.