IPSEC tunnel connection to another organization

Kind of an odd scenario here. I currently have ipsec tunnels to my vpn concentrator that act as a failover connections in the event that the primary connection fails but need to point them to another organizations concentrator (meraki firewall). If i point those tunnels to their destination address and the tunnels come up, will we experience any routing issues once those tunnels are established? As i said, these tunnels are not being used when the primary connection is up. Looking to do this because the other organization is taking over a few offices and at EoB and we will be disconnecting these offices from their primary connection, thus taking them off our network and allowing the other organization to gain access to these devices over the vpn tunnels. Im trying to avoid having to change things after hours and having to be consoled in to make the changes once the connection to our network has been severed.