You could do 1 of a few things
1) Perform a catch cup test on the water that is being put out by both your sprinklers and your neighbors, then with that information, create a custom nozzle that accounts for the output of both sprinklers. So if you measure your neighbor putting out 1.0 in/hr and your sprinklers put out 1.5 in/hr, then create a custom nozzle of 2.5 in/hr and Rachio will assume your grass gets watered that much.
2) Change your crop coefficient to a lower number. Warm season grass default is 0.65. If you drop that lower to say 0.4 (for example), you'll notice that your frequency of watering will decrease.....meaning the number of days between watering increases