There are possibly huge gap between caster and non-caster characters in a party. Caster have plenty of options of getting rid of own experience in exchange for various boosts. Item creation, wish making, less expensive XP spells, permanenting useful spells for himself and comrades. That may made him lose XP faster than he can compensate with common adjusting formula for characters lagging in levels.
The general opinion is simple "just by all costful spells in scrolls". XP is much under-priced and should never be used if it can be substituted with money.
But I have two objections. At first there are companies that gives players not so much gold. At second versatility is a general rule for d&d. You may achieve similar effect with pretty much different means. That also reflects in fantasy world economy.
So I'd like to design some way for willing characters to share their XP. So fighter that could cast no spells would have a way to return favor to wizard that do much enchantment for him.
There is one thing that should be strictly avoided in designed house rule. Players may not be able to force or talk NPC to transfer XP from them. Neglecting this issue will quickly break game session.
So I decided to introduce house rule with two guards.
First guard is amount of XP that may be reallocated by once: 1/2 of total XP earned by the party between two rests.
Second guard is tedious ritual that only willing creature having much time to spare can afford.
Teamwork benefit from PHB2 suits for this perfectly. This ritual would require much time to establish and would occupy team roster slot that may by used for something else useful by parties that have another member specialization. So using the XP sharing benefit would have fair price in discarding other options.
But I need two advices.
Is there any other more preferable way for XP sharing?
What training should look like and what requirements should be put on the task leader and task members if I would opt to use the teamwork benefit path described above?