"Undo" some transactions from backups
Not possible exactly as you intend, but here are some tools:

For your point in time, try a DB Snapshot: 

http://msdn.microsoft.com/en-us/library/ms175876.aspx

To revert from DB Snapshot:

http://msdn.microsoft.com/en-us/library/ms189281.aspx

Now that would revert in total, not leaving the intended T2, but would keep you from having to deal with restoring backups.

What you could do is with the DB still live and with a DB Snapshot available, then use a tool like Redgate for DML compare (compare live DB to DB Snapshot):

http://www.red-gate.com/products/sql-development/sql-data-compare/

You'd have to then pick and choose what DML you wanted to apply, and use Redgate to generate the script. Then you could revert with the snapshot, and apply the Redgate script to include only the DML you wanted to retain.

That's as close to meeting your requirement as comes to mind. Otherwise there's no way to say "roll this one back and not that one".