A ‘Lasso’ Tool is not available at present. This is an often requested feature so if deemed to add value will likely be on the list for action.
You can improve organisation by opening clicking on the Items Icon, next to the Undo/Redo Icons at the bottom left of the Screen.
You will find the Bodies that comprise your ‘Tracks’ and other Components there as Body 01; Body 02; etc.
Select each Body in turn, by clicking on the text [Body 01 etc], until you have selected everything needed.
Clicking on the text again will Deselect.
When your selections are completed click on the Folder with ✚ sign at the bottom of the Items pane.
The Selected Items will be placed in a Folder.
Now is the time to Rename the Folder by gently swiping the Vertical Bar ‘|’ at the extreme right end next to the Eye Icon to the left.
Use the Blue ‘Pencil & Paper’ Icon and Rename the Folder to, say, Track Assembly or title of your choice.
EDIT: Got the Track and Sled mixed up, but hopefully you will get my meaning.
Select this Folder and all the content will be highlighted.
Test Move the Selected Items and if any are left behind hit the Undo Button and then, within Items, Drag [press on the item to be moved and holding down drag to the appropriate location] the missing Body(ies) into the ‘Track Assembly’ Folder. Navigate separate Lists by moving to the top and pausing but keep holding while you do.
Following this you could Rename the Bodies in the Track Assembly Folder, then proceed to Rename everything in your Design?
If you need further help just shout.