Truth be told (and, again, this is my experience from competitive fighting rather than RQ rules), in a one-on-multiple fight (God, how I hated those!) you could still dodge to the same effect if you had your wits about you as the aim of the game then is to keep your attackers in a position where they can't get at you without getting in each others way (effectively turning the encounter into lots of brief one-on-one fights). Speaking as someone who has participated on both sides of such fights, I can say with confidence that it is no picnic for multiple attackers either as space is limited and, unless you resort to predictable and very limited thrusting (useful perhaps with shield and shortsword or spear in formation), your attack options become fewer than you might think. You need your wits about you to avoid braining one of your comrades or getting brained yourself by accident. There is, however, more of an advantage (as you might expect) to multiples attacking a lone combatant, although the margin is not as large as you might expect. I don't think I would play a free attack for multiples if a single opponent dodges as a matter of course but this would certainly be a fair decision (for ONE multiple attacker to have a free attack) in the case of a fumble. I would also be inclined to pop in a penalty of at least -10% to the single combatant from dodge rolls in suuch a situation (to reflect that the combatant has to be aware of the positions of all his attackers so as not to step into the path of another attack). The rules should accomodate this and it is certainly realistic. Hope this helps.
