Add members to a group.

Returns the Group containing its members.
Sample request body:
{
"groupMembers": {
"members": [
{
"href": "https://connect.calamp.com:443/connect/services/operators/2",
"rel": "operator",
"status": "Enabled"
}
],
"searchCriteria": [
{
"memberSearch": {
"type": "asset",
"searchTerms": {
"status": "Enabled"
}
}
},
{
"smartSearch": {
"type": "device",
"queryString": "name:LMU AND esn:123",
"accountId": 2
}
}
]
}
}