Bars for over/under 21?

Hi all! Coming up to Bellingham in a few weeks to celebrate a brother’s 21st birthday! We’re going to have some under 21s though with us as a group, are there any good bars where they allow under 21s but won’t serve them?

In my neck of the woods they have some where they’ll “X” your hand so bartenders won’t serve you or only give wristbands to 21+. Thanks in advance!