Example: This is for a landscaping business

We have a 3 forms -

1. Plant Names
2. Project Details (which includes a multi-select lookup picklist importing plant names from the Plant Names form)
3. Maintenance (also need to refer to the plants planted in a given project. This form has a lookup for the project name)

I am trying to find the best way to bring the selected plant names chosen in the "Project Details" form into the "Maintenance" form.

I have it set so that as a new maintenance report is added, the user will choose a project from a lookup field. So, how can I use the project name lookup to bring the selected plants into the maintenance form also? Is this not possible because they are a multi-select lookup within the Project Details form?

If anyone has any suggestions for the best way to cross-reference this data I am all ears.

Thanks.