Hi Subham
You can achieve the same by configuring "Package Filters" in Vault Package Builder Factory OSGI Factory Configuration (socialpubsync-vlt/desired config) on desired publish instance.
Filter format: path|+include|-exclude (package.filters)
Please find the attached snapshot for your reference, kindly do let me know if it helps.

Note : if you made the user to be part of any group, in that case sync will happen as for this case the sync is happening at group level with "rep:members" property and not on user level.
Thanks
Prem