You could do a script with the following
#loop
@getdammage (leader groupname) > 0.85
(leader groupname) setdammage 0
_pos = getpos (leader groupname)
(leader groupname) setpos [(getpos _pos select 0) -50, (getpos _pos select 1) -50, getpos _pos select 2]
goto "loop"
There are better (better looking) ways of doing it, this is just a rough example.
What this does is it heals the leader after he's got more than 85% of damage, and 'spawns' him near to where he died.
However, this only works if the script kicks in fast enough. ie. before ofp discovers that the leader is actually dead.