Load balancing on 2 VPN

[CHOUM]

Hello,

I want to know if it is possible to do load balancing on VPN? I precise.
I have a central site with 515E and a distant site with 2600 with 4 interfaces like this:


PIX--france provider--ukrain provider--eth2cisco2600
| |eth3
|-----------ukrain provider2-----|

so
PIX --- VPN1---eth2-----ukrain LAN
|------VPN2---eth3-----|

We use 2 providers in ukrain because lines reliability is not good.
First idea is to make a good VPN backup, second idea is to perform load balancing to transfer faster when the 2 lines works.

Thanx Michel