Support Pack install

I am going to install SP8a on a NW 4.2(SP6 currently installed) for Small Business server. I also have Groupwise 5.2 (SP3 currently installed) and I am going to install SP5 for that. My question is do I have to install SP5 for Groupwise immediatelyafter installing SP8a for NW or can I wait say a week or so. Thanks.
Phil