Spot/Listen and surprise rounds

[ffone]

Two groups are approaching through the forest (unaware of each other, but naturally they generally assume the forest might contain dangers, as adventurers always do).

As a DM I make secret spot/listen rolls to determine the first distance at which some character in one party becomes aware of the other party. (Assume that this is also within any 'max spotting distance' for the terrain).

Does the 'winning' character get a surprise round?

If so, does everyone in his party? (Assuming the spotter signals to them as soon as he spots the other group.)

If so, if the winning character's action (say, a Fireball) makes the opposing party aware (of the effect itself, like a Fireball, or perhaps of the caster due to the lower listen DC for the casting), do his teammates still get surprise round actions, or does the Fireball detonation become the time point for regular initiative / round 1?

[holywhippet]

It would work like this:

a) Character notices other group. DM tells character (assuming it is a PC) that this is so.
b) Character gets to make a decision on what to do - informing his party members is an option.
c) If he/she decides to attack they get a one person surprise round since everyone else has no clue what is going on.
d) If they informed their party, then it becomes an ambush situation - the entire party gets to make an action in the surprise round. The exception being if they try to hide/sneak first and get spotted.

Keep in mind, some class abilities/feats give characters a chance to act/react even during a surprise round.

[Luckmann]

If the player decides to inform his party instead of immediately taking his surprise round, let the enemy party take an extra Spot/Listen/Appropriate skills check, perhaps with a bonus adjusted by number of members of the player party.

If they make it, no-one gets a surprise round. If they don't make it, the entire player party gets a surprise round.

Sounds fair?