Well, the dragons are all adult, they are three (the players won’t be much more than two times their number) and you want to make the encounter short.
IMO you should head for a all-out-attack.
Furthermore, I do not believe, that the dragons would benefit too much from the guerillia-style attack... ( a long range spell as fireball would hit one with 13d6 = 45.5 pt of damage... they only have 230!)
First, consider not taking the standard-dragons. Roll dice for their stats (one is probably pretty good on charisma – the main-caster, one will be the fighting-machine and so on...)
Next we need to make use of their skills.
Use magic device can be very, very usefull, but let’s consider they have no magic items available (IMO they should at least get access to the magic items of their hoard!!).
Unexpected skills can be your best friend: Bluff, Hide, MoveSilently
Two of them should concentrate on Hide/MoveSilent, One should concentrate on Bluff.
Next – it’s your Battleground to prepare! IMO the dragons should make life hard for characters that do not fly.
Dig wholes in the ground in front of the forest. Take trees from the forest and throw them all over the place.
Now movement in very much limited, you can still move around freely and you got places to hide now.
If at all possible, you should fill at least some of the wholes with water = even better places to hide in.
Now it’s time for the party to show up.
They will start moving through the carnage toward the border of the forest.
They will see a dragon waiting for them. This will be the „Bluff“-Dragon. He will act as if one of his wings isn’t working and therefore he can’t fly. While the dragon advances slowly the party will concentrate on the dragon and on buffing themselves up – this is the time, where the two sneaky dragons can approach from both sides (if possible under water).
Now let’s consider meele. One dragon is probably not strong enough to survive much more than one round against a concentrated attack of the party. Therefore we need to do all to not come into this situation.
Begin the combat by casting Fog cloud/Obscuring Mist, Darkness and Summon Swarm. You probably have more casters than the group has – take advantage of that. Now the „wingless“ dragon takes to the air drawing half a circle and attacks with BW from an unexpected side. The other two wait on reactions from within. One could initially blast as well but at least one should wait on reactions.
Reactions that are very likely: Removing the darkness, possibly with daylight. This still leaves the swarm and the fog. An area dispel magic could remove more effects, but also remove their own buff spells. Now the dragons take turns – one renews one of the above spells (you could add grease & web to the list), One flies over and breathes the third reacts on the reactions within.
The one reacting should either renew a spell (if nobody comes out) or add another effect from the list.
If one or two come out he will use his AoO (consider giving most of them Combat Reflexes). With his reach of 15‘ (with his bite attack) and his blindsight ability he should get off a big bunch of AoO before the players even come near enough to attack. Then consider doing one (and only one) full round attack and either dive down into the nearby pool or take off into the air to come back from the other side. While this one takes to the air and will be back the next round with his BW, the one who casts will make sure, that those that came out will be inside some kind of obscuring spell effect again and the one who just breathed will come down (silently!) and wait on a reaction...
You might consider giving the Bluff-Dragon the „Improved Feint“ feat (3.5). Now he could Feint with a Move-Action (to attack using his bite/claw) and instead breath at the party. Everyone falling for the feint (very likely) will be negated his Dex – I don’t know if he fails his Ref-Save automatically then or does it without dex which probably results in the same category...
Since you are sorcerers you will have enough spells to keep the party occupied with your low-level spells. They could decide to make a strong wind to get rid of the fog but the penalty for using ranged weapons is pretty harsh in strong wind.
The rest of them should take normal buff spells. The hideout could be supported by spells like invisibility (only one needs to take it and can cast it on the others). Minor Image might add to the confusion inside the darkness/web-cloud.
Now that would be my first approach...
Azal