get one of these for each climber and clip into the anchor points with it with draws or lockers then get the second to do the same thing when they arrive.
since we are talking sport - it can be better for the climber who will lead the next pitch, to clip into the chain links if the anchor has chains, and have the belayer for the next pitch clip right into the anchor bolts, but not all anchors are set up this way so it may not be possible.....