Problem adding contacts to a CRM campaign that is from Backstage

I have integrated Backstage with Zoho CRM but am unable to add members to the campaign in the Zoho CRM contact. When in the contact page and selecting Campaigns to add, none of the Backstage specific campaigns show up as an option to add to the record. However when going to the Campaign tab it is clearly listed and working.

It seems that the only way to add is to click the Invite Prospects button on the Campaign page but that process is extremely difficult. I have several to add and am being forced to use the filter options instead of the search. And I see no way to import a list. This is extremely cumbersome and time consuming so I am hoping there is an easier way.

For some background, I am wanting to send an email from Zoho CRM to invite them to the Backstage event. I do not want to use the backstage template emails because you can not customize them properly. I would like to keep and control the communications inside CRM and be able to see the members like a traditional Campaign in Zoho CRM.

Any help would be greatly appreciated! TIA