Hi,

in the Odoo docs it says:

Workflow transitions can be restricted to a specific group. Users outside the group can not trigger the transition.

How can I achieve this in the xml definition of the transition?

This is my transition definition:

<record model="workflow.transition" id="paper_reviewed_to_accepted">
    <field name="act_from" ref="paper_reviewed"/>
    <field name="act_to" ref="paper_accepted"/>
    <field name="signal">accepted</field>
</record> 

SOLUTION:

make the transition only available to a group:

<record model="workflow.transition" id="paper_reviewed_to_accepted">    
    <field name="act_from" ref="paper_reviewed"/>    
    <field name="act_to" ref="paper_accepted"/>
    <field name="group_id" ref="module.xml_id_of_the_group"/>   
    <field name="signal">accepted</field>
</record>   

If you have a button to trigger the transition it is still visible to everybody. To only make it visible to the group, for which the transition is available, do:

<button name="in_review" type="workflow" string="Set to In Review" 
    states="submitted" class="oe_highlight" 
    groups="module.xml_id_of_the_group"
/>