I have 6 lights that each have an independent timer. Each timer is set to turn on and off at different times. I would like to incorporate another "master" switch that will allow me to turn on all the lights at the same time, independent of the timers (without turning the timers off) and when the switch is off, then all the lights would be controlled solely b their individual timers. Ideas?

You just need a 6 pole contactor/relay or 2
3 pole relays, 120 volt coil. When switch is on and relay energized, it will close the contact of each Timer connection.
Turning switch off would resume separate timer operation.