import re

regex = r"(?s):61:(?!.*:86:)(?:[\w /.-]|:(?!61:)[\w /.-]*)*"

test_str = ":61:2002190219C45612.4S202EXC:OL3654628815//CT56748005:86:/BENM/Unitech Imports/REM//58970.047:61:2002190219C30000S103LCADV5674920204//CT56748006:86:/BENM/Gravity Imports/REM//INV:/FEB20/446301:61:2002190219C45612.4S202EXCOL3654628825//CT56748005:60F:61:2002190219C45612.4S202EXCOL3654628815//CT56748018"

print(re.findall(regex, test_str))