this idea sounds really good but the execution is lacking.
this should be more like the eccentric billionaire inviting people over for a party, but terrorists plotting to take these rich men hostage infiltrate the party.
As thus, the garden should be more ornate, with real concrete pathways, hedge/bushes (that don't stop bullets), and multiple buildings surrounding the area, all interconnected. The garden would be the courtyard in the center, facing the driveway, which is fenced in.
In fact, I'm going to go build this idea right now because holy crap its good.