if you are having more clients,Go to Policies--->policy components--->Management server list ,Take a copy of the present management server list ,edit it and remove the Name--keep only IP address.Then assign this new list to the groups.Then you will not loose the clients...
Note:Above all sugesstions given by assuming that SEPM having a permanent IP address.It is always recommendable to keep a permanent IP address for the SEPM...