Generally, no, this isn't possible. You might try the WPAD Server
Extension on the Fiddler plugins page to see if you can get the other
devices to "autodetect" the Fiddler instance.
But the very first thing you should do is try to visit
http://thefiddleriphere:8888/
on one of the target devices to see if you're even bridging WiFi to
wired correctly.