Sick of being harassed...

Well, you could just to block them out, play some música with (or without) headphones when you pass them. Or you could walk início with a friend or sibling.
Ask someone older to drive you início from school,
or get a map of you local area and find another way to go home. If things get worse, (or even if they don´t) It´s legal to tell the police becuz what they´re doing is NOT legal. Try to talk to your parent(s) or someone who could deal with the probelm. Good luck! x)

You already know why they're targeting you so that's the first step.
Just because you don't know them doesn't mean you should let it pass by. I suggest you start a diary, write down the descriptions of the people (as you don't know them por name), where they are, what they do and say and how/if you retaliate. Start walking início with a friend, find another route to walk início por and tell someone.
They may not actually be able to help you - if you tell a teacher all they can do is offer conselhos and support as the bullies are doing it outside school property. However do they go to the same school as you? If they are wearing the school uniform whilst bullying you there may be sub-clauses to that so ask your headmaster/mistress. Ask if they have photo-books that show each and every pupil of the school and point them out.
Telling your parents may help. I remember when my younger brother was being bullied on his way início from school, he told his teacher and she didn't do anything about it as they were sixth formers and not in school uniform. So my younger brother told my mum, and she followed a few feet behind him on his way from school, pretending not to know him but walking in the same direction. She caught the bullies red-handed and since then he's had no problems. My mother doesn't mash words XD
Also when you write your diary about what is going on, go to your local police station and inform them of every little detail, every single time they do something. When you've compiled enough evidence the police will most likely take you mais seriously. If you aquire bruises photgraph them and keep them as evidence.