Question about Clan member starships

When a clan member sends a starship to one of your planets, what does that actually do? Does it cause the PW system to go to that planet map and start a game there? Is it a defender vs unallied startships? What does it do?

What happens if 3 clan members send starships to the same planet, and only 2 are playing on it?

The third player's starships remainns and are really annoying, becaue they block the limit / jumpgates for that player if the planet is now under your clan's control.

I think there should be a possibility to retreat the starships on a allianced or own planet.

I also think there should be possibilities to store starships on a own planet who will work together with the planetary defense and avoid that this planet would be played if this player is not in the battleroom.

If a clan is active in battleroom and there are at least as many clan players as clan players who send starships than the clan starships are used, else they are ignored and go back to that's player storage if it is captured by the same clan or a allied one.

It would be the best solution.