Using Dynamic Asset groups for reports is not possible. In fact, through custom reports you can do everything what you can do with dynamic asset groups (plus much more). If you would like to filter on IP addresses, create a report like the following examples:
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.IPAddress,
tblAssets.Lastseen
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Where tblAssets.IPAddress In ('192.168.10.1', '192.168.10.5', '192.168.10.6')
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.IPAddress,
tblAssets.Lastseen
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Where tblAssets.IPNumeric Between 192168010005 And 192168010010
Select Top 1000000 tblAssets.AssetID,
tblAssets.AssetName,
tblAssets.IPAddress,
tblAssets.Lastseen
From tblAssets
Inner Join tblAssetCustom On tblAssets.AssetID = tblAssetCustom.AssetID
Inner Join tsysIPLocations
On tblAssets.IPNumeric Between tsysIPLocations.StartIP And
tsysIPLocations.EndIP
Where tsysIPLocations.IPLocation = 'Example IP location'