So you want to use TRGO sourced from one of the OCxREF of "master" timer to start two slave timers (i.e. the slave timers have the slave-mode controller set in Trigger mode, TIMx_SMCR.SMS=0b110, set up for PWM but disabled, i.e. TIMx_CR1.CEN=0), but you want to start them on opposite edges of TRGO.
Unfortunately, you can't achieve that simply using the internal interconnections.
One workaround which comes into my mind is - at the cost of two pins - to connect externally the master PWM to one of the slave's CH1 or CH2, and use that as TRGI. The other slave would be started through the internal interconnection.
Another workaround could use a DMA triggered at the appropriate edge of the master timer, to write a value to one of the slave's timer's CR1 which would set CEN thus start that timer.
JW
