PL/SQL :: Query - Rows In Columns

I have following table -

CREATE TABLE     group_device
( group_id          NUMBER (8)     NOT NULL
, member_id     NUMBER (4)     NOT NULL
, device_id     NUMBER (10)     NOT NULL
, install_date     DATE           NOT NULL
, remove_date DATE
);

[Code]...

Current output does looks like below

10     1     123     23-MAY-12     28-MAY-12
10     1     456     28-MAY-12     01-JUN-12
10     1     789     01-JUN-12     
10     2     999     04-MAY-12     17-MAY-12
10     4     1123     22-JAN-12     27-JAN-12
10     4     1456     27-JAN-12     28-JAN-12

Device_id - Replaced_device_id - remove_date :: For group_id=10

e.g. for member_id = 1, device_id=123 got replaced by device_id=456 on 28-May-12
               device_id=456 got replaced by device_id=789 on 01-Jun-12

So output should look like this

10     123     456     28-May-12     -- Replaced     
10      456     789     01-Jun-12     -- Replaced     
10     789                    -- Active

Similarly there will be many groups, so it should list based on group_id