DOBJREF definition

Hello,

I'm trying to set up a MAXMIN optimisation and I want to use DOBJREF. I tried to define two references in HM2023 to point to 2 different responses with the same DOBJREF and HM doesn't agree with me - it says New entity id conflicts with existing id.

I found this in the help file for DOBJREF: "

1. The same DOID can be used for multiple DOBJREF entries. If only one DOID is used, only one MINMAX=DOID entry is needed in the Subcase Information section."

I defined two DOBJREFs with the same id manually in the deck I'm running but they were not read properly by HM - they got scrambled.

Am I defining it wrong ? For reference I'm trying to do a MAXMIN with a mass and a frequency response.

Thanks,

Chris