[Marcel]

In your command, first get the position of playerid.

pawn Код:

GetPlayerPos(playerid, X, Y, Z)

Then use a loop.

pawn Код:

for(new i = 0; i < MAX_PLAYERS; i++)

In that loop do a check with IsPlayerInRangeOfPoint.

pawn Код:

if(IsPlayerInRangeOfPoint(i, 10.0, X, Y, Z)

If that is true, send the message, if not, return false. Altough I recommend you to use foreach.