Free Port is propably doing something like this, so it might be your best starting point:
http://www.esoui.com/downloads/info404-FreePort.html
It has to match each guild and friendlist players position to Wayshrines position, then travels to the one closest to the target wayshrine.
Note that this will be quite a bit of data so you better update the dispalyed data in short burst (only one guild every second or so). And maybe only update it for the one map the player is looking at.
5 guilds with 500 people each can be 2500 people. Plus approxmiately 100 people friend list (not sure how much).