In case of 2 neighbour (or more) different faces - Will works with the volume's faces extremities! ;)

A possible method (the funny game is to find the more speedy effective one! ;)
- Select & Copy Move the 2 faces
- Delete original (easy because yet selected)
- Select Perimeter (careful to not select the vertical middle edge(s) !!! )
- Extrude WITHOUT Cap Ends!!!
- Join All
- SubDivide



Of course can be multiple if you take the same length of Extrude! ;)
(there is an optic effect of record, extrude goes from faces to piece as post above)