Here is my question

I have the following network. We run a hosted datacenter. We use a Mikrotik AH1100x2 as our core router. In the datacenter, we have our corp network, (Red), which has a tunnel to our main office, (also in red). This is an EOIP tunnel.
We also host other clients in our datacenter. Typically they have EOIP tunnels to other bridges on our Mikrotik which are connected to separate VLANS. (See the Blue and Green Networks) These networks use the AH1100X2 as their default gateway as well and have EOIP tunnels to their respective main or branch offices. All this is working properly.
The problem is that I have a new Client, (Client D in Orange) In their main office they use as their IP addressing scheme, the same IP range as Client A does. This means that I cannot create an EOIP tunnel to them because as soon as I do, Client A cannot reach their hosted servers.
So I created an IPSEC tunnel between our Mikrotik and the client. What I need to do is set it so that the clients on bridge5, are routed to the IPsec tunnel rather than to bridge2. I need traffic on all 5 brides to be completely isolated from one another.
I cannot change the IP addressing at any of the offices. I suspect that I will have other clients that use the same IP, that I will need to form tunnels too.
Any ideas?