More than one sensor going at a time is highly unlikely (unless getting fouled by something upstream).
The fault codes associated w/ O2 sensors don't mean sensor is bad but rather the value being reported by them is outside of spec. Sure it c
ould me sensor itself is bad but more than likely it means there is another problem up stream... and doubly so when more than one goes at a time.
What codes are you getting? And more importantly, what work was recently done?
With a multi-meter you can easily test each sensor to see if it's truly dead.
Good luck
