You can do this by:
[groupname] exec "check.sqs"
In the check.sqs type
_group = _this select 0
_cnt = 0
_units = units _group
_count = count _units
#lop
_dammage = getdammage _units select _cnt
_cnt = _cnt + 1
?(_cnt == _count) : goto "out"
goto " lop"
#out
exit
then each time you can do with your _dammage all what you need
example :
after _dammage = getdammage _units select _cnt
type
?(_dammage > 0.
: _units select _cnt sidechat "I`m hit"