InnerWeld. This addon welds parallel connected selected edges
together.
Documentation
First go to User Preferences->Addons and enable the InnerWeld addon in
the Mesh category.
Go to EditMode, select some parallel edge(loop)(slices). Handles ALL
edges parallel next to each other.
These edges will be welded together when invoking addon (button in Mesh
Tools panel).
If you wish to hotkey InnerWeld:
In the Input section of User Preferences at the bottom of the 3D View >
Mesh section click 'Add New' button.
In the Operator Identifier box put 'mesh.innerweld'.
Assign a hotkey.
Save as Default (Optional).