Order proposal only in first week of month

Hi,

We are using SAP F&R.

We have certain vendors who supply only in first week of month. e.g week 45 in 205

We are not able to use normal Planning Calendars for such vendors.

In MD27, the periods have to be continuous.

i.e. I cannot put dates like  from 01.11.2015 to 06.11. 2015,   then second period as 01.12.2015 to 06.12.2016. Because the dates should be continuous. i.e. there can be no GAP between the dates.

There is a Time Stream id in F&R. However this is assigned at Location level, hence even that cannot be used.

In Procurement cycle(/FRE/SCHEDULE), if i select "every 4 weeks", and Monday,  there is no guarantee that Monday will come in the first week of the month.

Please mention if there is any way to make sure that Order Proposal are generated only in first week of the month.

Regards,

Girish