Jenny Giolas is right, SOLIDWORKS does not officially support virtual environments for Workgroup PDM.
However, what that means is that the help you will get from SOLIDWORKS support is limited, maybe none. I still encourage you to try it, there is a very good chance it will work like a charm, or better yet, go for PDM Standard since Workgroup PDM has one foot in the grave.
This is a bit of an interesting one, it might be a documentation oversight actually. According to SPR 490929, SOLIDWORKS officially started supporting Virtual Environments for Workgroup PDM starting with 2015 SP1. I believe that was one service pack after they started supporting VMs for SOLIDWORKS and EPDM, which could explain the oversight.
It's pretty safe to assume that the same systems that are listed as supported for the Enterprise PDM Servers will also work well for Workgroup PDM.
As Martin Solem mentioned it's worth a try, Workgroup PDM generally works fine on VMWare, especially in the situation you mentioned where it's for training purposes and not a full production vault.