In reply to Kuldeep:
Many people think they want to control the number of bins they have in a covergroup, but it’s much easier to control the number of covergroups that you have. If each covergroup has 1 bin, then you create as many covergroup instances as you have slaves.
BTW, there will be an enhancement to the 1800-2012 SV LRM that will make it easier to program bin construction, but it will be at least a year before you will see it implemented.