You've actually got quite a bit of complexity wrapped up in this one play.
A1 driving to the hole, starting from T's area. This is the "base case" that is usually decided in pre-game. It sounds like you pre-gamed that L has the dribbler, even though it originated from T's area.
B2 comes over as a secondary defender. Normally the official who does not have the dribbler normally has primary coverage on secondary defenders.
B2 establishes LGP. B2 becomes a new primary defender, possibly changing coverage once again. Depending on whether this happens immediately before contact, or there is time for the "primary" official to pick up the new defender, will normally determine who has primary coverage on any contact.
A1 dishes off then runs over B2. At this point, you no longer have a block/charge. You have a "pass and crash". This also needs to be pre-gamed. The usual options are L goes with the ball and T/C stays with the crash, and vice versa. If you discussed "pass and crash" in pre-game, then you will know which of you had primary coverage on this call. If you did not, then "somebody" has to make that call. And you are somebody.
