4G Bonding using other Peplink Devices

We have a Peplink balance that has a Speedfusion bonding setup. One of the feeds into the bond is a device that we bought before the peplinlk that creates a 4 SIM card bonded VPN WAN link for us. That VPN is now part of the Speedfusion VPN and, yes I can already hear you shouting - “a VPN in a VPN - why would you do it”. But the reason that I am posting to get away from this legacy hang up that I have. So my thoughts are to have 4 BR1s that are providing separate WAN connections to the Balance. Sadly the balance cannot be near the antennas as line lose would degrade the signal too much thanks to rack location. Does anyone think my solution is good? Is there an issue with this design that I have over looked?. Thanks in advance everyone.

Can you provide a graphical diagram on what you want to achieve?

Thank you.