Without knowing your manager's reason, I'm guessing that maybe too many requests are being escalated without good cause. Since your main concern is appearing friendly then you will have to follow your manager's instructions with total transparency.
Instead of just saying no, explain to your co-workers that requests cannot be automatically escalated anymore. Then review the request and ask how you can help solve the problem so escalating isn't necessary.
You will know which ones have to be escalated but remember if you get the first one over with, the rest will be easy. Telling your manager you had no choice but escalate the request might make him irritated. If he seems mad or says something rude, appear oblivious to everything he says or does because once he realizes you are right, he won't feel so stupid if he thinks you weren't paying attention.
TIP: The best way to combat someone's mad irritation or yelling is with a big smile. Just keep smiling and watch anger melt into frustrated confusion.