Convert Item from Finished Good to Kit Assembly Finished Good

One of my clients sells magazines. Historically their item MAGAZINESKU was purchased as a finished good from a single vendor who produced the entire item. Now, however, the magazine is being produced by two vendors. One produces the covers (COVERSKU) and the other produces the inside pages (INSIDESKU). These are still sold as the MAGAZINESKU item.

What is the best way to go about purchasing COVERSKU and INSIDESKU then assembling them to create the finished good of MAGAZINESKU in inventory?

If I was starting from a blank slate, this seems like a clear Stock Kit with Kit Assembly. However, MAGAZINESKU already exists as a Finished Good and it is NOT already setup as a KIT. I do not believe I can simply convert it to a kit. 

Acumatica Cloud ERP 2022 R1
Build 22.114.0029 
Distribution Edition

Thanks, 

David