Show me the rule

[WestMichBlue]

Between games Saturday my partner and I were discussing unique plays/calls that we had during the season (He was from a different city; I hadn't worked with him before, but he was good.)

He described a play that I thought we had discussed here. Bloop bunt down 1B line, very quickly you had F2, B-R, the ball, and F3 all in a small space. F2 fields ball and B-R collides with F3 smack in the middle of the baseline (not yet to the 30' point).

He asked my opinion; I said obstruction on F3, citing the oft-repeated statement here that you only protect one fielder for interference, and you have to judge which fielder has the best chance to make the play. Obviously that was F2 here, so if F3 can't get an interference call, then she must be guilty of obstruction. (Of course its a HTBT, you might have a case for 'train wreck' and let it go.)

Anyway, we did not agree and when I tried to prove my view with the books (ASA or NFHS, Case book or POE) I couldn't find it.

OK guys and gals - if you are only going to protect one fielder, please show me the rule - or interpretation.

WMB