the ability to assign multiple Parents to an opportunity

Often when creating opportunities for commercial projects, there are multiple company's tendering to win the same job who all require pricing during the early stages. Currently to work around this, we have to create duplicate opportunities for each individual parent (company) and remove these opportunities value so as not to effect our Opportunity Forecast. If we were able to assign multiple parents to the one opportunity during the sales and quoting process, it would allow us to associate all involved companies under the one banner and keep forecasts much more accurate, saving lots of time and keeping our opportunities organised. Upon progressing this opportunity through the sales process, one of the parents could be awarded (selected) as the awarded parent of the opportunity prior to the opportunity being completed.