EDIT: As is the way, I figured this out less than 2 minutes after posting. I’ll add the solution into a reply to this thread in the hope that it helps someone.
I’m trying to narrow results in a repeating group. I’d like the following constraints on a repeating group:
Only show Start Dates that are within X days from current date/time
X days is decided by the person who creates a listing. This is saved within a number field called ‘Unlimited days’. I’ve tried to create a few different filters on the RG:
Example: Start Date < Parent Group Listing’s Unlimited days from current date/time.
However, I can’t do the ‘from current date/time’ in this case, and I’m also not including the actual +(days): source. I changed things round and tried to use an ‘Advanced:’ constraint, but I still can’t it working.
Here’s an image of a couple of attempts. Note that I’m not using +(days): here, and I definitely should (but I couldn’t fit it in!).
Any help is appreciated 
