Link the PGN of a JFIN to a channel inside an External Function, to vary the PGN

Hi,

I want to create an External Function that will contain a JFIN. 
When I will import the External Function, I would like to be able to vary the PGN property of the JFIN.
At the moment, it seems that the PGN property of the JFIN can only accept integer number, it cannot accept an integer coming from a channel.
If I insert the External Function in my project, I will not be able to change the PGN property of the JFIN because it will be locked. And I do not want to change it to the same PGN value for all the occurences of the External Function.
I would like the PGN to be a FGI to the External Function.

My use case is that I want to control Hawe PSx CAN valves where they have a different PGN for each valve section. It would be neatly integrated inside an External Function so I could reuse it for all the different valve sections I have in my project.

Any workaround?

Thank you and have a good day!