how to edit groups in group picker which are stored in database as groupids with a related action from a form

a!localVariables(
  local!groups:a!forEach(
    ri!attendees,
    togroup(fv!item.groupid)
  ),
  
 a!formLayout(
label:"Update Meeting Information",
contents: {
a!columnsLayout(
columns: {
a!columnLayout(
contents: {
a!textField(
  label: "Meeting Subject ",
  labelPosition:"ABOVE",
  value: ri!MMS_Meetinginfo.subject,
  saveInto: ri!MMS_Meetinginfo.subject,
  required: true,
  validations: if(
    len(
      ri!MMS_Meetinginfo.subject
    ) > 50,
    "Value may not be longer than 50 characters. You have entered " & len(
      ri!MMS_Meetinginfo.subject
    ) & " characters.",
    null
  )
),


a!paragraphField(
  label: "Meeting Body",
  labelPosition: "ABOVE",
  value: ri!MMS_Meetinginfo.body,
  saveInto: ri!MMS_Meetinginfo.body,
  refreshAfter: "UNFOCUS",
  height: "MEDIUM",
  required: true
),


a!textField(
  label: "Location",
  labelPosition: "ABOVE",
  value: ri!MMS_Meetinginfo.location,
  saveInto: ri!MMS_Meetinginfo.location,
  required: true,
  validations: if(
    len(
      ri!MMS_Meetinginfo.location
    ) > 50,
    "Value may not be longer than 50 characters. You have entered " & len(
      ri!MMS_Meetinginfo.location
    ) & " characters.",
    null
  )
)

}
),
a!columnLayout(
contents: {


a!pickerFieldGroups(
  label: "Attendees",
  labelPosition: "ABOVE",
  maxSelections: 2,
  value:local!groups,
  saveInto:{
    a!save(local!groups,union(save!value,save!value)),
    
  },
  required: true

),
a!dateTimeField(
  label: "Start Time",
  labelPosition:"ABOVE",
  value: ri!MMS_Meetinginfo.startTime,
  saveInto: ri!MMS_Meetinginfo.startTime,
  required: true,
  validations: if(ri!MMS_Meetinginfo.startTime>now(),null,"start date time must not be past date time  ")
),



a!dateTimeField(
  label: "End Time",
  labelPosition:"ABOVE",
  value: ri!MMS_Meetinginfo.endTime,
  saveInto: ri!MMS_Meetinginfo.endTime,
  required: true,
  validations:if(ri!MMS_Meetinginfo.endTime>ri!MMS_Meetinginfo.startTime,null,"end date time must not be less than start date time  ")
)


    }
  )
      },
showWhen: ri!MMS_Meetinginfo.startTime-time(0,10,0,0)>gmt(now(),"IST")
 ),
a!cardLayout(
      contents: {
        a!richTextDisplayField(
          value:a!richTextItem(
            text:"Meeting that you want to update is either ongoing or been completed",
            size: "MEDIUM_PLUS",
            color:"ACCENT",
            style: "EMPHASIS"
          ),
          align:"CENTER"
        )
      },
      height: "AUTO",
      style: "INFO",
      marginBelow: "STANDARD",
      showWhen: not(ri!MMS_Meetinginfo.startTime-time(0,10,0,0)>gmt(now(),"IST"))
    )
  },
  buttons:{
  a!buttonLayout(
    primaryButtons: {
      a!buttonWidget(
        label: "UPDATE MEETING",
        icon: "envelope",
        saveInto: {
          a!foreach(local!groups,a!save(ri!attendees,append(ri!attendees,{groupid:tointeger(fv!item)}))),
          a!save(ri!MMS_Meetinginfo.startTime,gmt(ri!MMS_Meetinginfo.startTime,"IST")),
          a!save(ri!MMS_Meetinginfo.endTime,gmt(ri!MMS_Meetinginfo.endTime,"IST")),
          a!save(ri!MMS_Meetinginfo.createdBy,loggedInUser()),
          a!save(ri!readOnly,true)
         
        },
        submit: true,
        style: "PRIMARY",
        showWhen: ri!MMS_Meetinginfo.startTime-time(0,10,0,0)>gmt(now(),"IST")
      )
    },
    showWhen: ri!MMS_Meetinginfo.startTime-time(0,10,0,0)>gmt(now(),"IST")
    
   
  )
 
  }
  
  
)

)

i have a requirement like i need to send a meeting form that is been assigned to a set of groups and there should be a related action that can add or delete groups within that meeting form

for  selecting groups i have used a group picker and stored that selected values as ids within a cdt attendees with meeting id as primary key and i have got this groupids using this meetingid and stored into a

 local variable by converting that groupids to groups in related action form but i when i remove a group that is already existing it is geeting removed here in the form but it is showing within the record 

can anyone explain how can i solve this problem

this is the code related to related action from and ri!attendees store groupisds related to a meetingid and ri!meetinginfo stored meetinginfo

it is a start form with process model that is writing the updated data i.e group data to db