PSObject with relational values - one to manny - powershell

Question

want to populate the following PSObject so it can have a one:one or one:many relationship between IPs and hostnames.
$hostobj = New-Object PSOBject
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value ""
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value ""
This gives me the correct headings but when I try add more than one value, it will error one trying to add the repeat values:
$hostobj = New-Object PSOBject
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value "1.1.1.1"
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value "server1"
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value "2.2.2.2"
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value "server2"
Why is this?
Can do the one to many bit fairly easily:
$hostobj = New-Object PSOBject
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value "1.1.1.1"
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value "server1", "server2", "server3"
Either of these is the data set to extra from:
1.1.1.1 server1
2.2.2.2 server2
3.3.3.3 server3
4.5.6.7 server4 server5 server6 server7
8.8.8.8 server8
9.9.9.9 server9
1.1.1.1
server1
2.2.2.2
server2
3.3.3.3
server3
4.5.6.7
server4
server5
server6
server7
8.8.8.8
server8
9.9.9.9
server9

Answer 1

you want to create a list of objects like:
$ArrayList = New-Object System.Collections.ArrayList
$hostobj = New-Object PSOBject
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value "1.1.1.1"
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value "server1"
$ArrayList.Add($hostobj)
$hostobj = New-Object PSOBject
$hostobj | Add-Member -MemberType NoteProperty -Name "ip_address" -Value "2.2.2.2"
$hostobj | Add-Member -MemberType NoteProperty -Name "hostnames" -Value "server2"
$ArrayList.Add($hostobj)
so that $ArrayList contains all the host objects. and each object has one value for ip_address and hostnames.
If this does not help you please specify what you expect/what exactly you are trying to do/work with.