How create dependencies between multiple topologies ?

[loan75]

Hello,
I am quite new with tosca concept and xopera parser but i can't find a "clean" solution to my problem.
Let say that there is a template that deploy a secret store solution (like Hashicorp Vault). We want to allow a client to deploy one and only one Secret store (this part can't be implemented with tosca, so it will be manage by our application, right?).
BUT, let say that we have another template to deploy some servers. These servers will then store the root password in the secret store solution previously deployed by the other template.
I am not sure how to create this relationship between the topology of a unique secret store solution and multiple topologies of servers.

I don't think that having one template to merge all that is a good solution (i think that scale will be a problem), but i don't think that it's possible to make some relationship between distinct topologies. Am i right?