borabora,
Bidding to fly with certain individuals has been a practice a three airlines that I have worked for. These are two of the methods that have been employeed:
1) FO bids close after Captain bids. This allows FO's to rearrange there bid choices based on which Capt. is flying what line.
2) Allowing a pilot to request a certain other pilot to fly with. This gives crew planning the option to prioritize that pilots bid with his choice of crew member to fly with.