Per-invoice label/category ?

I've received the following question from farmers willing to use INv5.

they want to know whether it is possible to categorize invoices based on the type of work they do for 3rd-parties: sometimes it's silage, sometimes bundling, etc.
the clients are the same, but they would like to have an overview per type of work of the running invoices, and of the totals (how much money did silage bring back, how much for bundling, etc.)


I see the following 2 solution:
1. There would be the possibility to create a company per type of work, but as the clients are mostly the same, this would require a synchronization of the clients (is such a thing possible?)
2. Another solution would be some labeling feature, as we are all used to on Github/GitLab, where each invoice could be assigned a series of labels, and it would be possible to filter based on those labels afterwards.