Purchase id should have acces to vendor creation only not customers

Can anyone help for below scenario:-

The purchase department used to create business partner of vendors only.He should not have access to customer creation.The purchase id should have access to create the purchase raw item master data.

In the sameway sales , sales user should have access to create the customer business partner only and sales user should have access to vendors list. As well as sales user should have access to create the item master data to the group they assigned such as sales data.