Hi,
single counter bus can be selected by multiple eMIOS channels in OPWMB mode, but this counter bus defines PWM period. For OPWMB mode you can individually set duty cycle, means position of first and second output edge, but not the period individually.
In OPWFMB mode you can have individual periods per channel, but in this case channel is counting its internal counter, and this mode is not supported on each channels.
BR, Petr