How can I assign an IP address to a user account on WordPress?

Question

To provide a bit more context, the website is publicly accessible but with restricted content hidden behind a membership program. However, for corporate accounts I want to limit their access to just their static IP, preventing access outside their work environment (unless they use a VPN or RD).

What's the best method to link their WP user account with their static IP, so that account can only login and authorized to see the content when in the office? Obviously, this would only be for corporate accounts, single memberships are already limited to two active logins.

Any help would be much appreciated with this conundrum!

I thought about using whitelist on the htaccess, but this isn't the solution as those on a single license membership are liked to by on a dynamic IP.

Many thanks in advance