A simple function that splits a string IF and ONLY IF the condition returned by the call to the first argument is True.

conditionalsplit.py

from argparse import ArgumentError

def conditional_split(split_function, input_string, separator=None):

	# splits the string into a list
    result = input_string.split(separator)

	# makes the check in each item of the list
    for x in xrange(len(result) - 1):
        try:
        	# checks if the function returns True for both sides of the split
            if not split_function(result[x], result[x + 1]):
            	# If not, undo the split by popping the two sides of the split
            	# and inserting a merged string in the location instead.
                part_a = result.pop(x)
                part_b = result.pop(x + 1)
                print "{0} + {1} = \"{0} {1}\"".format(part_a, part_b)
                result.insert(x, "{0} {1}".format(part_a, part_b))
            else:
            	# If yes, then print for debugging reasons!
                print "{0} | {1}".format(result[x], result[x + 1])
                
        # stops whenever a IndexError is hit. tries to preserve the result acquired
        except IndexError:
            print "Index {0} is {1}.".format(x - 1, result[x - 1])
            break

		# makes sure the function argument has a correct number of arguments
        except ArgumentError:
            raise ValueError(repr(split_function) + " has a invalid number of arguments!")

    return result


# splits only if in both sides of the split, one of the words separed by "," are also one
# of the words in the other side separed by ",".
my_func = (lambda x, y: True in (z in y.split(",") for z in x.split(",")))
# the input string
my_string = u"abdicate,much abdicate,awesome so,much so,cool so,hello idk,guys,so,cool why,so,then,awesome"
# prints are good! :)
print my_string
# do it! do it!
my_result = conditional_split(my_func, my_string, " ")
# prints out thy result
print "{0} from {1}".format("|".join(my_result), my_result)