How one master simultaneously control multiple slave?

Hi

When a master has connected two slave, the connection interval between them will like what?

Is it like following:

I          I          I          I           I.....

Two salve have common initial point?

Or will be like following:

I                    I                      I......

     I                    I                     I                   I......

Two salve have differently initial point?

Is it able to achieve the following situation by using the BLE STACK 1.4?

One slave have blue LED , the other have red LED.When master has connected two slave,whether the master can simultaneously turn on two LED( not turn on one by one )? two slave communicate with master by GATT/ATT procedure.

Thanks in advance.

PS:

The chip i used is CC254x.