[GNC] Projects/classes for transactions

[BANO notIT]

Hello,

I am wondering if there's any possibility to assign projects to 
transactions. My use case is to filter transactions across several 
expense accounts (transportation, food, entertainment, etc.) for trips. 
And would be great to be able to draw graphs based on that trips.

Something called Classes is mentioned in wiki 
<https://wiki.gnucash.org/wiki/Project_and_Design_Documentation#Features_and_Functions> 
and seems to fit my use case. But I can't understand if it's already 
implemented or is just considered. Neither I was able to find anything 
about it inside the app (ver. 5.8).

Are there any techniques that will allow me doing these things? I'm 
wondering if Job could work as a substitution.