Configure your crystal passband filter in a capacitor ladder network formation such that the crystals are connected end to end and that a capacitor is connected between each crystal connection node and ground.
Increase the number of crystals and capacitor stages in your capacitor ladder network to narrow the frequency selectivity (tuning capability) of the passband filter. The bandwidth of the passband decreases and the attenuation of frequencies outside of the passband increases as the number of ladder stages increases.
Calculate the values of the capacitors in the quartz bandpass filter with one of any number of passband filter calculators (see giangrandi.ch). Enter in the crystal electrical specifications provided on the manufacturer's data sheet in the text boxes in the passband filter calculator and click the "Submit" button to obtain the capacitors required and a frequency response plot of the calculator.
Simulate the design of your quartz ladder passband filter with a circuit simulator to evaluate the frequency and time domain responses. Include simulator models in the simulation that the crystal manufacturer and the capacitor manufacturer has available. Also include accurate models for the traces that will connect the crystals to the capacitors in your circuit board. Run the simulations over temperature extremes. Simulate the filter for worst case reception scenarios, such as when signals with high power frequencies just out of the passband are present and frequencies that are within the passband are present but severely attenuated.
Modify the values of the capacitors in the crystal circuit based on circuit simulation results and the desired frequency and time domain responses. Change the capacitor values incrementally to determine the optimum value for the specific frequency and time domain response specification you must meet. Add compensation capacitors in parallel with the crystals and simulate to fine tune the passband's frequency and time domain response.