triple flare?

On Sat ~23:00 PDT from 47.74N, 122.65W I observed 3 faint satellites
flare in the same spot about 1 minute apart along the same path. Due to
trees to the NW and shadow to the E, I only saw them for about 45
degrees of the pass. They appeared to come out the NNW headed to ESE.
They each were quite faint - barely visible - but flared very brightly
when each was highest; about 60 degrees up in the ENE for about 5 seconds.

This is the second time I've seen 3 satellites in the same close orbit
flare in the same place, but I didn't record the previous observations.

Any ideas? Heavens-above.com didn't help.

TIA,
Andrew.

PS: my apologies for inexact observations. I'm a very casual observer,
but this ones bugging me, twice over now.