You could try using the ifExist functionality in Maths:
Defines values for specific channels, even if the channel is currently undefined. The channel does not need to be present in the current list of defined channels. 'x' will be any valid math channel expression.This will provide the channel from the Gen1 data if it is there. If it is NOT there, it will provide the channel from the Gen2 data. You can name these maths channels something generic and usable, so for instance if the RPM channel has a different naming convention between Gen1 and Gen2 cars, you could name the channel [RPMboth] and then always use this channel for RPM. This way, regardless of which Gen car data you are viewing, RPM would always be available.
You can write these channels as follows:
Please note that these channel names are defined by Porsche.