I'm concerned that we may not have a clear picture of how a group is defined. I only say this because, depending on some unstated conditions, the dates above will either form one giant single group, or 3 groups where one group dominates the set.

Missing grouping conditions?

1. Does this 15 day rule cascade? If a record Y starts 10 days after another record X, and then there is another record Z started 10 days after that, then does this form one group of three records X,Y,Z, or two groups each containing two records X,Y and Y,Z? I made the assumption that the 15 day rules cascades to form larger groups.

2. Are the dates inclusive? For example, if one record has a start date and then a dead date many months later, do all days within that range get merged into the group? I treat both possibilities in my quick analysis below.

Potential Groupings

So, if we begin with id 7714, we see that the start date is 1/27. Clearly, the next entry 7882 starting on 1/28 falls in this group. Notice however that 7882 ends on 5/15, so anything which starts within 15 days of 5/15 must be added to the group.

Thus, 19690through 21210 get added to the group, which via cascading leads to 21918 being subsequently added to the group. The cascading has consumed nearly all entries in the set. Call this GROUP A.

If, however, the grouping is date inclusive as well, all entries from 13190 up to 17124 must also belong to GROUP A, and now all ids are in a single group.

If the dates from GROUP A aren't inclusive, but actually strictly adhere to the '15 day after' rule with cascading, then instead you would have a second group composed of 13190 through 14020, and a third group with a single entry, 17124.

Essentially, my question is, do any of these match your intended grouping, or is there some other information we're missing in the group definition?

I'm concerned that we may not have a clear picture of how a group is defined. I only say this because, depending on some unstated conditions, the dates above will either form one giant single group, or 3 groups where one group dominates the set.

Missing grouping conditions?

1. Does this 15 day rule cascade? If a record Y starts 10 days after another record X, and then there is another record Z started 10 days after that, then does this form one group of three records X,Y,Z, or two groups each containing two records X,Y and Y,Z? I made the assumption that the 15 day rules cascades to form larger groups.

2. Are the dates inclusive? For example, if one record has a start date and then a dead date many months later, do all days within that range get merged into the group? I treat both possibilities in my quick analysis below.

Potential Groupings

So, if we begin with id 7714, we see that the start date is 1/27. Clearly, the next entry 7882 starting on 1/28 falls in this group. Notice however that 7882 ends on 5/15, so anything which starts within 15 days of 5/15 must be added to the group.

Thus, 19690through 21210 get added to the group, which via cascading leads to 21918 being subsequently added to the group. The cascading has consumed nearly all entries in the set. Call this GROUP A.

If, however, the grouping is date inclusive as well, all entries from 13190 up to 17124 must also belong to GROUP A, and now all ids are in a single group.

If the dates from GROUP A aren't inclusive, but actually strictly adhere to the '15 day after' rule with cascading, then instead you would have a second group composed of 13190 through 14020, and a third group with a single entry, 17124.

Essentially, my question is, do any of these match your intended grouping, or is there some other information we're missing in the group definition? I'm sorry for such a long-winded answer, but it doesn't appear that your tentative requested output meets your grouping definition.

With clarifications, I'm sure that we can sort this problem out.