Free Master Calendar option in JIRA or at least ability to create and use maybe a project as one?

[Sarah Vigue]

Hi- I have 2 clients that I want to track in JIRA. I'd like to customize a Master Calendar template of projects and milestones. Ex. Client #1 has monthly Campaigns and these campaigns have many milestones that need to be hit. I'd like to have this for Client #2 as well. 

How can I achieve this in JIRA if there are no gadgets that are Schedules, calendars or anything similar? I'd love to share it with my team too. Any suggestions?