yui2 to jQuery DOM get value of a variable Code Translatiion

Question

Like the title says I try to make this in jQuery ("Groups" is an ID of a ComboBox):

var groups = YAHOO.util.Dom.get("Groups");
var group = groups[groups.selectedIndex];

var elem_name       = YAHOO.util.Dom.get(group.value+"name");
var elem_members    = YAHOO.util.Dom.get(group.value+"members");

Of Course the var groups isn't such a big problem the main problems are the var elem_name & the var elem_members

var groups = $("#Groups")[0];
var group = groups[groups.selectedIndex];

//Does of course not work
var elem_name       = $(group.val()+"name");
var elem_members    = $(group.val()+"members");

with normal javascript it works but i want to know how i do somthing like the following in jQuery

var groups = $("#Groups")[0];
var group = groups[groups.selectedIndex];

//normal javascript
var elem_name       = document.getElementById(group.value+"name");
var elem_members    = document.getElementById(group.value+"members");

Any suggestions?^^