If you are on Rhino 7 you can just double-click the edge to chain the edges during fillet.
For the NextRadius, that depends on how you execute the command. If it’s by icon, just change (Shift+RMB on the icon) the command to
! _FilletEdge NextRadius=0.25
Then it’ll start from 0.25 every time you run the command. This of course has the disadvantage of losing the ability of using the last value.
If you just want it to just start with 0.25 but still have Rhino remember the last used value, you can add
! _FilletEdge NextRadius=0.25 Enter to the “Run these commands every time Rhino starts”-section of Options>General.