Making an item "conversable" but not equippable

[temnix]

I have a piece of equipment that can store gold. This is done through a dialogue that is started via the "conversable" button. When the gold is loaded, the item becomes too cumbersome for monks and kensai to wear. I can exclude them, however, then the button through which gold can be taken back out also disappears for them. This doesn't make sense by itself, but the player could give the item to somebody else - unless he plays in solo mode. Then he is going to put the gold inside (the item is replaced with the heavy version) and not be able to take it back out. What are my options for making an item unequippable but usable? Anything? The effect "Disallow item" sounds like it could let the button remain, but it isn't an item property, it must be imposed from the outside by a special spell, and then some characters may end up not covered and so on, this is too loose.