SQL Server 2012 :: Compress Table Timelines

Here is data I am working with:

CREATE TABLE HISTORY(CUSTOMER VARCHAR(10), PLANNBR VARCHAR(10), SUBPLAN VARCHAR(3),
STARTDATE DATETIME, ENDDATE DATETIME, HISTORYMONTH VARCHAR(6))
INSERT INTO HISTORY(CUSTOMER, PLANNBR, SUBPLAN, STARTDATE, ENDDATE) VALUES('9111111', 'H1111LAC', '006', '2014-01-01', '2014-05-31', '201401')
INSERT INTO HISTORY(CUSTOMER, PLANNBR, SUBPLAN, STARTDATE, ENDDATE) VALUES('9111111','H1111LAC', '006', '2014-01-01', '2014-05-31', '201402')

[code]...

I need to compress these segments into records which will look like this. The HistoryMonth column is not used to make the final determination of records to keep.

CUSTOMERPLANNBRSUBPLANSTARTDATEENDDATE

9111111H1111LAC0062014-01-012014-05-31
9111111H1111OC0102014-06-012999-12-31
9111112H1111LAC0062014-01-012014-05-31
9111112H1111LAC0182014-06-012999-12-31
9111113H1111LAC0062014-01-012999-12-31
9111114H1111LAC0062014-01-012014-02-28
9111114H1111LAC0062014-04-012999-12-31

Customer 9111111 shows a change in both PlanNbr and SubPlan 2014-06-01 Need to show both records
Customer 9111112 shows a change in SubPlan 2014-06-01 - Need to show both records
Customer 9111113 shows no change in PlanNbr or SubPlan - Need to show 1 record
Customer 9111114 show a break between and enddate and next start > 1 day - need to show both records