@kevinjh, I moved here from San Diego (home of triathlon) where I got really spoiled. We had 5000 members in the SD Triathlon Club and every night of the week there was 3 or 4 free training events/classes by professional coaches. I completed 22 triathlons in 3 years.
Moving here is a different story. There are only a couple of bike / tri shops in my area. One you might want to check out is http://www.11afondo.com/v8-fashion/seccion.php?menu_id=b&
. This is in Belgrano on Av. Congresso.
I did find this training group http://www.grupof.com.ar/
I must admit it was hard for me to get into the idea of training for triathlons here in BsAs. There is no open-water swim course like La Jolla Cove's 4 km course and I just didn't feel like always being on guard while riding my Focus (the wheels alone would pay someone's rent for months). I left my bike back home in Philly.
After a lot of thought I decided to switch sports to inline speed skating. There is a very large contingent of skaters here in BsAs and I have less worry of someone stealing my skates off of my feet.
Also, the availability of parts (wheels and bearings) is much better than bike parts.
Having said all of that I can think of no other sports that offer such a complete training program than triathlon. Completing a triathlon is an accomplishment. Hook up with the guys at 11 Fondo. They do go on long weekday rides. However, their English is very, very basic. The guy who runs Grupo F has much better English.
If I see you on your road bike I'll tuck in behind you on my skates.