Can a computer with one Wi-Fi adapter both connect to a Wi-Fi network and share Inteet over Wi-Fi?

I will explain my use case but I am asking about what is technically available with Wi-Fi technology, so please don't submit alteative solutions as answers.

I have a MacBook Air and a cheap Windows netbook, each with Wi-Fi.

My home Inteet is provided via Wi-Fi with a captive portal that only allows me to long on with one device.

I want to be able to use both the Windows and Mac laptops on the Wi-Fi Inteet provided where I live.

When I ask non-technical people about this they all seem to think it's not possible. I'm technical but I suck at networking.

A Wi-Fi adapter can obviously both send and receive so there doesn't seem to be a hardware reason this is not possible. But perhaps the Wi-Fi networking protocols were not designed with such a possibility taken into account?

So can Wi-Fi technically solve this problem? If so what terminology is used for this so I can read up on it? If not, what are the limiting factors that prevent it?

Recent Questions...