My cleint has a one big master catalog which is integrated with ERP, he wants to spilit this into a smaller catalogs that are specific to each country's website.
a) Is there any out of box feature that provides -this ? b)Any one has done similar requirements ?
There is nothing out of the box to do this.
As a general solution which I have known to work quite effectively is to develop a custom sync which can sync items from the Online catalog of the master catalog to the Staged version of the country's specific catalog.
Master:Staged ----normal sync----> Master:Online -----custom sync----> Country:Staged.
To develop the custom sync you essentially want to extend
In here you can work out what must be synced and what can be excluded. I cannot post you the complete solution, but this is fundamental basis of it. If you wish to override product attributes during the custom sync so they have values which are specific for that country catalog, then you should look at extending
Hope this helps.