IMO, your staging grounds should always have resupply facilities of some sort.
Have your ships move to the resupply depot at the frontier, and then move them out from there.
If your trip to the frontier is more than 2 or 3 systems, it is highly likely you will have a planet close enough to the default path that you can redirect ships with minefield tags.
code:
@ = warppoint (destination and/or source of ships)
o = planet (with resupply depot)
. = empty space
x = minefield tag
-|\/ = path of ships
.@....
..\...
..xO..
..x|\.
..x||.
....@.