Q: Airport Express 802.11n as router + wireless?

Hello: We have rural highspeed (1.5 Mbps downloading, 0.5 Mbps uploading), brought into the house by an antenna which receives a signal from a radio tower nearby. A cable runs from the antenna into the house, and is connected to a router, in this case, an 802.11n Airport Express. I have the Airport Express connected to my MacBook Pro (mid 2012) via an Ethernet-to-Thunderbolt adapter. The internet connection works as expected.

My question is, can I create a wireless network for others to use while also maintaining the "hardwired" antenna-to-MacBook Pro connection described above?

Regards, Alison