Yes, you can share one Machine room audio unit for up to 8 shafts.
Right-hand group of 8 jumpers: address setting. If the machine room is shared by multiple lifts, you can use one audio unit and set more addresses with the available jumpers. This is impossible with other types of audio units!
If the machine room audio unit is shared by shaft number 2, 4 and 6, then you have to put each from 3 jumpers into the address setting field according to the number of the shared shafts.