Welcome amp11220...
Not sure how long you are staying...
But,
For 8-10 guys, that is just about a van full.....there are many expat locals that can take your group wherever you want to go...look in transportation thread and favorite drivers. One lucky dog, pops, pura visa transport.....there are many good ones.....that would be your best bet....
As far as girls go for a party....
Honestly, half the fun about taking 8-12 guys to HDR is checking out, talking with, and closing a deal with a chica. The next morning at breakfast everyone bullshits each other about how great there night was.....
More specifically...I would get the SL courtyard rooms so you can party in common area. If that is not available, I would get penthouse for main party/bachelor and everybody else get a room at SL or LA.
Seriously, 8-10 buddy's hanging out at the Del Rey picking up chicas....that is pretty fun!!!
Than hire a driver to take you wherever....if it was me....I would take everyone to Jaco for a night or two...than day trip or over night to MA. Costa verde or La Mariposa hotel (bring a couple of the best chicas and share)...
You are going to need some pictures for the wife's back home....make sure you go zip lining, river rafting, or fishing....and tell everyone back in USA you did it for 3 days it was so fun. For $40 Rio tropicales gives you a picture disc with 300 pictures of you river rafting....I tell my wife and friends it was a 3 day trip... :
Good luck!
Call the SL or LA in advance and for a small fee they can probably arrange everything.