[Joel]

There's currently no way that smart guides can take into consideration components of a group, table, or subgraph, but that sounds like a good idea (so long as it doesn't get too aggressive).

Question: When you speak of "locking to leads", are you in fact attempting to connect lines to elements of the group?

If so, you can set lines to connect to the components of a group in the Connections Inspector (as opposed to the group as a whole), it may not be a suitable workflow for you as I suspect you're not actually connecting in an attempt to have perfectly horizontal or vertical lines.