Banks want assurances from U.S. regulators that they will not be barred from certain businesses before agreeing to plead guilty to criminal charges over the manipulation of foreign exchange rates, causing a delay in multibillion-dollar settlements, people familiar with the matter said. In an unprecedented move, the parent companies or main banking units of JPMorgan Chase & Co (JPM.N), Citigroup Inc (C.N), Royal Bank of Scotland Group Plc (RBS.L), Barclays Plc (BARC.L) and UBS Group AG (UBSG.VX) are likely to plead guilty to rigging foreign exchange rates to benefit their transactions. The banks are also scrambling to line up exemptions...