On Wednesday, 13 Sep 2017 at 14:01, Göktuğ Kayaalp wrote:
> I have tried the following:
>
> <2017-09-18 Pzt 14:25-18:40 +1w>--<another date>

I think this is discussed in the FAQ on the org mode web site but, in
any case, no, you cannot do what you want.  You may wish to look at 
,----
| org-clone-subtree-with-time-shift is an interactive compiled Lisp
| function in ‘org.el’.
| 
| (org-clone-subtree-with-time-shift N &optional SHIFT)
| 
| Clone the task (subtree) at point N times.
| The clones will be inserted as siblings.
| 
| In interactive use, the user will be prompted for the number of
| clones to be produced.  If the entry has a timestamp, the user
| will also be prompted for a time shift, which may be a repeater
| as used in time stamps, for example ‘+3d’.  To disable this,
| you can call the function with a universal prefix argument.
| 
| When a valid repeater is given and the entry contains any time
| stamps, the clones will become a sequence in time, with time
| stamps in the subtree shifted for each clone produced.  If SHIFT
| is nil or the empty string, time stamps will be left alone.  The
| ID property of the original subtree is removed.
| 
| In each clone, all the CLOCK entries will be removed.  This
| prevents Org from considering that the clocked times overlap.
| 
| If the original subtree did contain time stamps with a repeater,
| the following will happen:
| - the repeater will be removed in each clone
| - an additional clone will be produced, with the current, unshifted
|   date(s) in the entry.
| - the original entry will be placed *after* all the clones, with
|   repeater intact.
| - the start days in the repeater in the original entry will be shifted
|   to past the last clone.
| In this way you can spell out a number of instances of a repeating task,
| and still retain the repeater to cover future instances of the task.
| 
| As described above, N+1 clones are produced when the original
| subtree has a repeater.  Setting N to 0, then, can be used to
| remove the repeater from a subtree and create a shifted clone
| with the original repeater.
`----

-- 
: Eric S Fraga via Emacs 26.0.50, Org release_9.0.9-573-g09e612