you mean using ropes equalised from anchors back to you not to a central power point ?
if so, use the method described (and in the 1st picture) for when anchors
are out of reach, put a klemheist sling around all your ropes - equalising and considering direction of pull. Link the prussik to this sling, release belay plate slowly to load this set up.
Then you can use your tie-ins (remember to stay attached somehow) to create a powerpoint
and tie the live rope into them via a munter-mule (locked off italian hitch) and remove the prussik and kleimheist