How to expand jinja inside imports for GCP Deployment Manager

I have a Deployment Manager template/schema and I want to dynamically include different startup-script options for cloud-init depending on the template.yaml I am calling. In my template.jinja I have:

      metadata:
        items:
        - key: startup-script
          value: |
{{ imports['startup-script-pre']|indent(14, true) }}
{{ imports['startup-script-custom']|indent(14, true) }}
{{ imports['startup-script-post']|indent(14, true) }}

All the imports are included in the final output, however the jinja2 inside of them is not processed, it leaves things like {{ env["name"] }} in there for cloud-init to fail on. Inside the GCP console the Expanded Config looks like:

systemctl daemon-reload
systemctl enable {{ env["name"] }}
systemctl start {{ env["name"] }}

which obviously cloud-init has no idea how to deal with.

Is there a way to force those imports to be processed for jinja instead of just inserted raw?