Not for CB GroupJive Wall, but it's possible for CB Activity. For CB Activity within CB Activity > Parameters > Activity > Parser set "Prepare Content" to "Enable". This allows Joomla content plugins to parse activity posts. Next install CB Replacer Bot, which is a Joomla content plugin for replacing inline text. You'll need to create the appropriate REGEXP to search for your strings and replace them. Aside from that you'd have to try acting on the following triggers in CB Auto Actions to extend the parsing in CB Activity and CB GroupJive Wall with your own.
CB Activity:
Code:
$_PLUGINS->trigger( 'activity_onParse', array( &$this, $ignore, $html ) );
CB GroupJive Wall:
Code:
$_PLUGINS->trigger( 'gj_onDisplayWall', array( &$row, &$menu, $group, $user ) );