I have a master collection of items with unique ID's.
At some point I have a subset of IDs from the master list that belong to some sub grouping if you will. The subset is just a reference of IDs of items that exist in the master list. Is there a way I can ask the master list for just the items that match the IDs in my subset without having to loop through the entire master collection?
Just trying to find the fastest way to do this rather than the standard loop.

```
   //go through master list and determine which items belong to this sub item grouping
    for (var item = 0; item < masterListItems.length; ++item ) {
      for (var subItem = 0; subItem < subItems.length; ++subItem ) {
         if (masterListItems[item].Id == subItems[subItem].Id) { //if it is a sub item
           //do some UI specific thing
         }
      }
    } 

```