Nested Repeats - Accessing Outer Repeat Values in Inner Repeat

I have two nested repeat regions, accessing server connect data from outer and inner. The data available from these server connects is:

outer.data.outer.id
outer.data.outer.outer_name

inner.data.inner.id
inner.data.inner.outer_id
inner.data.inner.inner_name

I have my nested repeat like this:

dmx-repeat:r_outer="outer.data.outer"
   dmx-repeat:r_inner="inner.data.inner.where(`outer_id`, "**OUTER_ID**", "==") "
      <p>{{**OUTER_ID**}}</p>
      <p>{{outer_name}}</p>
      <p>{{id}}</p>
      <p>{{inner_name}}</p>

What do I put for **OUTER_ID** to get the value of outer.data.outer.id?