[BoBzY]

new int:var1, int var2;
new Float:entorigin[3];


public Check(const String:output[], caller, activator, Float:delay)
{
	if (var1 == caller || var2 == caller)
	{
		//stuff
	}
}

public Action:GetEntId(Handle:timer)
{
	new entindex=-1;
	while ((entindex = FindEntityByClassname(entindex, "func_button")) != -1)
	{
		GetEntPropVector(entindex, Prop_Send, "m_vecOrigin", entorigin);
		if (-50.5 == entorigin[0])
		{
			GetEntPropVector(entindex, Prop_Send, "m_vecOrigin", entorigine);
			var1 = entindex;
			HookSingleEntityOutput(entindex, "OnIn", Check);
		}
		if (-50.8 == entorigin[0])
		{
			GetEntPropVector(entindex, Prop_Send, "m_vecOrigin", entorigine);
			var2 = entindex;
			HookSingleEntityOutput(entindex, "OnIn", Check);
		}
	}
}

Code is too long, this may help ya? =)