Any trick to getting a concatenated text list with more than 150 items?

Essentially, I am trying to get a combined text list with more than 150 items (closer to 1500). As this cannot be done with a combined text field, are there other work arounds?

My use case:

Cost Table: Includes records with a project ID and amount
Invoice table: Includes records with a project ID and amount

Their only common table is a parent table called Project ID. Table Project ID has many Costs, and many invoices.

I want to check if a particular ID/Cost in the Invoice table, exists in the costs table. A simple way is to make a Formula Text field in my cost table called IDandCost.

Summarize that up to the Project ID Parent, then lookup back down to Invoice table. A simple 'Contains' formula can check. However, this is only good if my summary field has 150 or less entries. It has closer to 1000+.

How can I accomplish this goal? My only thought right now is a synced table where IDandCost is the key field, and work the magic that way. Is there a quicker/easier solution?

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Mike Tamoush
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