Sync & Async Synchronisation on SQL Server 2012
Is it possible to set up async synchronisation (high-performance) on MS SQL Server 2012 globally


Yes, with AlwaysOn Availability Groups having commit mode set to asynchronous commit for a replica.  That'll be by-database, so you'll have to group the databases into the AG that you want to see that happen with.


  but somehow force synchronous replication for one table between nodes


It really depends on your definition of "synchronous", but in the truest of definitions then no, you can't have synchronous commit for individual tables.  It'd have to be by database/availability group.