It might be easiest to use the MikroElektronika Click boards for WiFi.
Otherwise I'd suggest ESP8266 modules, using TTL (3.3V) RS232. These can be used as is, or programmed with NodeMCU or Forth. The ESP-01 module is simplest; it needs 3.3V supply and the serial pins. The centre of the star would be configured as an access point, and the outer rim nodes configured as stations. You're up for fabricating some mechanical support for the module. Also some programming of each module.