I have never used an RTE in a dialog. Typically your RTEs are inline text and have their own 'dialog' field.
When using multiple RTEs, have you tried nesting them directly into your components markup?
For example, say i have the following 'cool-component'.
cool-component.html
<div class="my-cool-component"> <!--/* Grab a property form the dialog */--> <h2>${properties.heading}</h2> <!--/* Create a 'syntetic resource' RTE */--> <div class="rte-1" data-sly-resource="#{'primarytext' @ resourceType='foundation/components/text'}"></div> <!--/* Insert an image for dialog */--> <div class="cool-image"> <img src="${properties.imagePath}" /> </div> <!--/* Create a 'syntetic resource' RTE */--> <div class="rte-2" data-sly-resource="#{'secondarytext' @ resourceType='foundation/components/text'}"></div> </div>
When doing it this way, I would also create a 'cq:template' node for this particular component that defines some properties of 'primarytext' and 'secondarytext'. Let me know if you need an example of using cq:template nodes next to a component.