I agree with "wirenut".
The Resistor would be really large and waste a lot of power [true power, in watts or Kilowatts]. The wasted true power in the Resistor will result in a lot of heat [which is the wattage dissipated in the resistor].
As wirenut said, look for a Transformer with the output voltage required, along with the total KVA required.
You could use a 250 VA [0.25 KVA] 120 x 12 VAC Transformer to drive all 5 of the lamps in Parallel. This would be a much safer method, as to eliminate 120 VAC from being present at the low voltage lamps.
Scott SET
