Multi-basing support weapons

Hey guys,

I'm using GW style bases for my collection. I have all my basic infantry on 25mm rounds. I have 40mm rounds as well, but they are somewhat too small for a three man team weapon.

Would it work, rules wise, to model the weapon with two crew on a 40mm round, and the third loader/assistant on a separate 25mm base? I figure it would also help squeeze the weapon into smaller areas, although I'm not trying specifically to model to advantage. More just trying to use what I have on hand.

Thoughts?