The Hammers have been linked with two Austrian players in the past.
The Premier League trio's emissaries will reportedly be joined by their counterparts from Atalanta, Ingolstadt, Stuttgart, 1860 Munich, Freiburg, Shakhtar Donetsk, Anderlecht, Schalke and Hamburg.
Okotie, who plays for 1860 Munich, has scored 24 goals in 57 appearances for the 2. Bundesliga side but is out of contract at the end of the campaign.
The report claimed United were quoted £20million by Dragovic's employers Dynamo Kiev, but the defender's valuation may be slightly lower as he approaches the final two years of his deal.
Stoke's Marko Arnautovic also features in Das Team's squad, though the reason for Southampton's presence is much less evident.