Yes you could so long as the relay is rated above the total current draw of all three lights and the power feed wiring is correctly sized and fused. Take the wattage of each light x number of lights = total watts. Take the total watts / by the battery voltage = total amperage.
100 watts x 3 = 300. 300/12 = 25 amps. Use a relay rated at 40 amps. Fuse should be at least 30 amps. Wire size minimal 12 ga from battery to relay and beyond to where you split to the individual leads to the lights. From there you could down size to 14 or 16 ga wire
2001 Ranger Edge 3.0 V6, 5 speed M/T
Limited Slip Differential, James Duff Traction Bars
Kumho 30x9.50 15 MT / Black 297 Series 15x7 Rims