A little late but still:
Doing the same with a lte 4g stick; isc does not support full umts/hsdap (?whatever it's called)3g4g sharing so you need to download third party virtual router called connectify me pro, which is obviously a payed app.. you can try to get unofficial versions nevertheless.. this way plug the 3g/4g stick to our pc, use connectify me - you still need to set internet sharing in windows (or whatever platform you're using) , so set source 3g4g adaptor to allow sharing over local (wired) network and set all services to allow and/or set ports nbers if necessary - stick the etherner cable to pc lan and router wan (!yes wan!).. now connect your pc to the router's wireless network and enjoy.. every other device that is connected to the router is on one network.. only con is that you need to be connected with the host pc to the wireless network at the same time as sharing over wire.. erhernet connection can only share internet, the network's still set by the router's dhcp server..