The SoftImage XSI 3d modelling and animation software package was one of the first 3d modelling packages I got really good with back as a high school and college student. Blender, while being a dream, lacks a robust method for selecting sets of vertex one at a time and then merging them in the order of selection. One day I decided to tackle this problem and made a small addon that adds a new menu and the previously described merging behavior!
INSTALLATION
-------------
Method A) Simply download the release and drop the kadavar folder in your Blender 'Addon' folder.
Method B) Open Blender -> Go to `File` -> Settings -> Addons -> Click install addon and select the kadavar .ZIP -> search for Kadavar in addons (it should appear under Experimental)
PARAMETERS/HOW TO USE
--------------
Select at least two vertexes (can select up to atleast 64 vertexes in sequence currently)
Alt + K to access the behavior menu
Select "Merge at Point" option to see the magic
Enjoy my creation which for years has helped me save hours on 3d modelling and focused more on animating and texturing instead!