While I understand the benefits of "bees" are we sure that is what the OP has? Could they be wasps, yellow jackets, etc.?
we had a problem with yellow jackets going in and out of the mast head
last year when I needed to go up the mast for a job. We soaked a rag in wasp spray, attached it to the halyard
that exited the masthead where the bugs were going in and out. Added a line extension to the halyatd and hoisted the soaked rag to the top. "Slapped" it hard against the masthead several times to get the insecticide as far in as possible.
Next day, no more activity. Went up the mast, worked for an hour. No problems. Good luck!