Just use docker-compose? Put multiple containers in one compose file. Create an internal network for them to communicate with.

https://github.com/awesome-selfhosted/awesome-selfhosted#wikis

Your docker-compose looks overly complicated…

Here is mine.

version: "3.7"
networks:
  docknet:
	external: true
services:
  guacamole:
	image: jwetzell/guacamole
	container_name: guacamole
	volumes:
	  - postgres:/config
	ports:
	  - 8080:8080
	networks:
	  docknet:
		ipv4_address: 192.168.1.8
	restart: unless-stopped
volumes:
  postgres:
	driver: local
#default login is guacadmin/guacadmin