c concenterate on one grp in which u r confident enough to get thru,and just sit for another grp with some preperation,so that u'll b able to clear one grp and for othr u'll get the experience and can prepare well to get thru in next attempt,otherwise its not mandatory to gv both the grp evenif u hv paid the fees.
and anyhow ur attempt will b counted,so its better to give both the groups..............all the best......................