is possible to do some groups like in XSI, where if you select it, it select everything that is inside?

i have 3 controllers for the leg, and i want to be able to select them all at once insted select each every time.

First look at Groups and Bundles. I'd opt for Groups if you are at /obj. Just hit the “x” key in your network view to open up the group view. Now drag/drop objects to create a group. You can select groups of objects in one go.
There are also bundles that support multiple objects in different directories. Not just limited to a single directory. The Bundle list lives in a dedicated panel.

Then look at the Channel List. You can create groups of channels. You can get your scoped channels there.

Next have a look at the character picker.

RMB On an HDA and choose Character Picker option.
Just select your objects then press the add button in the character picker. You get a new “dot”. Drag that dot where you want in the char picker.

You can dump any image in the character picker.

WOW" thanks Jeff, i didn't know that Houdini have so many ways to group things like that, i will look more info on the character picker, that sound very similar to the armature system of Messiah animate.

tonight i have more to learn.

Another way is to add a selection script to each one of those objects that picks the other two objects. This will get annoying with any groups of objects larger than 3 though.