So the explicit answer to your question is no. You can not sequentially load tags. However this feature is coming in the next major release of utag.js (no release date as of yet).
For your example thought it sounds like you can fix your issue, by bundling the tags inside the utag.js file. As the issue you described, sounds exactly like a network request race condition. Where the tags will be called for in order, however they will be processed in order that they return.
When they are bundled, as they are already there, there is no network race condition, so they will be called in order that you have configured in the UI.
Hopefully that makes sense, and will help with your timing issue.
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