Dan,
We don't currently support IN style queries in RQL yet. We are planning to add this but in the meantime you could use a LIKE query. Unfortunately I have found a bug in the LIKE query for the realtime endpoint so you will need to upgrade the 2.6 core when we push out the fix.
When the fix is ready you can use a query like this:
/rest/v1/realtime.json?like(xid,DP_62.*)
In the LIKE query you can use the dot star notation for a wildcard. For example
test.* --> Matches test_1 or testAgain
.* --> Matches everything
.*test --> Matches 1_test or againTest
We use Regular expressions for string matches in RQL so any of the Java regex patterns and classes are valid so long as you escape them properly in the URL.
But this will likely return more than your desired results if other XIDs match that pattern.
I would suggest either placing all the points under some path in the point hierarchy and then using this query:
/rest/v1/realtime.json?like(path,my_path_to_points)
Or renaming the XIDs to something more meaningful for this purpose:
DP_groupA_member0
DP_groupB_member1
Or using the point name in the same manner.
Thanks,
Terry