I want to prevent situations where multiple salespersons create quotations that together exceed the available stock, leading to conflicts when customers confirm their orders.

example :
we have 5 items of product in the inventory sales person number 1 send Quotation of 5 ,another sales person send also 5 to a customer, the both customers accept the quotation so we will get into problem which is the quantity conflict

is there any idea of how we can deal with that, 
or quantities be reserved from the warehouse while creating the quotation so we avoid conflict.


I know it would not be the best practice but I'm asking.