The 2013-2016 RRS rewrote rule 20 which deals with room to tack at an obstruction. Rule 20.3 now allows for a hail to be passed on to an additional boat, even if the passed along hail no longer satisfies rule 20.1.

This applies well to the case of a stack of boats just after a start. As the leeward most boat approaches an obstruction, she can hail the boat to windward for room to tack. The windward boat must respond by either tacking, or replying "you tack" and giving the leeward boat room to tack and avoid her. If the windward boat is planning to respond by tacking, they can pass the hail on to the next boat in line, even if they are not close enough to the actual obstruction to satisfy 20.1.

As far as your rights as the tacking boat, the rules says:
20.2 (c) The hailed boat shall respond either by tacking as soon as possible, or by immediately replying ‘You tack’ and then giving the hailing boat room to tack and avoid her.

So, the boat that hails must be given room to tack and avoid the boat to windward, but you are still a port tack boat upon completion of the tack and must give way to the rest of the starboard tackers.

Moral of the story- if there is a short distance from the pin to an obstruction, make sure that pin is favored so you have an escape path!