Without details or specifics, it's difficult to give a helpful answer. In general, it is usually not a good idea to have an unbalanced set of stays on each side of the pier. Cable stayed bridges are borne out of practicality, in this case construction method. One pair of cables support one segment of deck (be it precast, cast-in-place, or prefarbricated girder) as the bridge is incrementally constructed. At some stage you would have to deal with the imbalance in cables, and it's a complexity that would best be avoided (it's difficult enough with a normal case!). If you did have to deal with some imbalance in load, it would be better to keep an equal pair of cables and increase the number of strands per cable from one side to the other.
Secondly, it would best be answered by a member of your design team with a good background in cable-stayed bridges. If you are new to this type of bridge design, this would be a very challanging case to start on and nothing can replace good experience.
Best of Luck