2 Iron type of wilderness tile can be connected by assining the similar to oasis, but into a scouting tower duo that gets report of any army passing by from between.(only teutons option)
2 clay type wildernesses into a pair the has a road - villages next to these roads get 50% faster movement on merchants and armies (Roman option)
2 Woodland wildernesses makes a trapped ditch made by gaul and steals 1res from every passing raid or traps some troops or slows down enemies by 10% who are attacking through the paired wilderness areas.
Or
Use only 1 tile of each wilderness and have the same bonus effects work with 2 tile radius of that wilderness tile