I found that setting the cluster's 'Resilience Policy' to 'Do Not Migrate Virtual Machines' seems to have the desired effect while still letting me manually and via 'Maintenance' migrate VM's

Thanks all

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Mark Steele
CIO / VP Technical Operations | TelVue Corporation
TelVue - We Share Your Vision
800.885.8886 x128 | msteele@telvue.com | http://www.telvue.com