Best thing to do is nothing. No eye contact, no shouting back, nothing. Unless you have perfect Castellano with a Porteno accent, as soon as you open your mouth it will be obvious you're not from here, and it will just encourage it more.
I live in a similar location -- I have a lava-auto and a mechanic on my corner. There's up to 15 guys hanging around at the lava-auto always asking if they can help me etc.
If you start listening carefully you'll realise the large majority of the comments are harmless -- yes occasionally you get some grossities but usually they are cheesy -- You're a Goddess, What Eyes you Have, God must have pulled the Stars from the Sky etc etc -- it's not often that I've actually heard something disgusting.
If the guys are actually following you at all, then there is cause for concern -- do you know the porteros on your block? I know most of the ones in my street by sight and they'd all tell the guys where to go if I was being bothered.
Start saying hello to the porteros and shop people etc in your area -- if someones following you, go into one of the stores or talk to a portero -- they are usually very nice and would walk you to your building if you needed it. If the guys are following you go to the closest building and ring the bell for the portero -- tell them you are from next door and having a problem etc. Whoever's bothering you should get the idea and go away, and if not tell the portero of the building that your having aproblem with the guys and they should be able to look out for you.