Two things come to mind: Since you want to access two networks simultaneously, you need two virtual NICs in the guest (add another via Virtual Machine > Settings > "+" button > Add Network) and two virtual switches: one to the wireless interface, one to the wired interface. The default setup tracks the host's current network interface (which is why you can't access the 192.168.252.* subnet when wireless is active).

To add a virtual switch, you'll need to edit /Library/Application Support/VMware Fusion/boot.sh (sorry, there's currently no GUI). DaveP wrote a guide for these sorts of edits - if it doesn't cover your exact setup, it's still a good starting point: Scripts to manage Fusion network settings and How to modify Fusion network settings whitepaper

It's in the post etung referenced: How to modify Fusion network settings whitepaper

You need to read and understand VMware Fusion Network Settings - Part 1.pdf and look farther down the post for "Here's the first quick update on adding a new bridged adapter and configuring the VMX file."

vmnet2 is the additional Virtual Switch.