Castle Reinforcement

So i've been thinking, what if clan people can help us while attacking? So it's like when we don't have troops in our castle the clan shield logo thing will still be in the troops line while attacking, for example we want to ask for help from our clan mates while attacking, we just need to place the castle somewhere allowed and our clan mates can only deploy their troops from our castle (remember: this will only work if we ask). So while we're attacking and we place the castle shield sign thing somewhere this will appear in the clan chat:

SilverSky is attacking SkySilver, help?
HELP | IGNORE

more or less it's like that
This will also work for defending, so when all the troops in our castle deployed (if there are troops) this thing will appear on the clan chat:

SilverSky is defending against SkySilver, help?
HELP | IGNORE

If we have no troops in our castle then the 'thing' up there will appear as soon as a troop gets into the castle range and again our clan mates can only deploy their troops from our castle.

One last thing ONLY LIMITED NUMBERS OF CLAN MATES CAN HELP (clear?) maybe 5 clan mates or 3 or 10.

And will this take much server power? If yes, then I'm sorry.

Well, that's it, tell me what ya think about this idea