displaying DL members

The script below get the transport rule based on the GUID and then display also the exemption group for that rule. WHat i want is that to display also the member of the exemption group (ex. FromMemberOf) 

If i check the content of the variable ($group.FromMemberOf) I would see that it has 2 DL groups (pic 1).  But if i try to use FOreach-Object to display further its members i get an error that it cannot convert the identity (pic 2). Is it because the variable being stored is of different type?

Param(
    [parameter(Mandatory=$true)][string]$sid,
    [parameter(Mandatory=$true)][string[]]$ExchGuid)
    
# Arrays
$TRule_Info = @()
$DL_Info = @()
$DL_nested = @()
$From_Member = @()
$From_MemberInfo = @()

foreach ($rule in $ExchGuid){
    $TRule_Info = Get-TransportRule | where guid -EQ $rule
        foreach ($group in $TRule_Info){
            $ht = [pscustomobject]@{
            SID = $sid
            RuleID = $group.Guid
            RuleName  = $group.Name
            Reject_Code = $group.RejectMessageEnhancedStatusCode
            Except_MemberOf_DL = $group.ExceptIfFromMemberOf
            Except_SentTo_DL = $group.ExceptIfSentToMemberOf
            SentToMemberOf_DL_BlockGroup = $group.SentToMemberOf
            FromMemberOf_DL_BlockGroup = $group.FromMemberOf                                            
                                           
            }
                                                          

# Displays the information of the Transport Rule as per defined in var $ht
$DL_Info += $ht
        }
}

$DL_Info

PoSH newbie, BaSH Oldie