The central government has constituted an informal group of three senior cabinet ministers to work out a compromise formula on the quota issue, which will take into account the interests of all sections.The group comprises defence minister Pranab Mukherjee, HRD minister Arjun Singh and finance minister P Chidambaram, informed sources said today."It is neither a committee nor a panel... the three ministers will be meeting in order to work out a mechanism, a formula" to resolve the issue, the sources said, adding that no time-frame has been fixed for finalising the formula.