Blanket Order Management

We are in the process of a 9.0 implemenation.   Our planners need to know how long it will take a supplier to react to a new blanket order  so they can create that new blanket in time to prevent a stockout between blankets.  In other words, Supplier A can supply a part in 3 days once a blanket is established, but want 60 days to set up a new blanket once the current one is fufilled.  Our planners today are loading 60 days in our item masters today, but this cannot be used in E1 since the leadtime will be