sales territory mapping

I am trying to build a sales territory mapping tool. I have pulled a list of all accounts with greater than $1B in revenue. I have pulled that data and consolidated it into number of accounts by state. So, I now have column worksheet!A:A contains state abbreviations, column worksheet!B:B contains count of companies with greater than $1B in revenue. 

On a second worksheet I want to allow a sales leader to add state abbreviations to a column(Territories!B6:B30) and immediately return the number of accounts for that territory. This column would be of variable length. It may only have 2 states or it could have 20. How do I make a formula that will search column worksheet!A:A for any number of states in Territories!B6:B30, then total the value from column worksheet!B:B where the values match?

I know I can do this several different ways that require more steps, but I want a simple formula. Thank you.