# Replace Regex help

**URL:** <https://community.fibery.io/t/replace-regex-help/5499>\
**Category:** Get Help\
**Created:** [December 6, 2023, 3:37pm UTC](https://community.fibery.io/t/replace-regex-help/5499 "2023-12-06T15:37:17Z")\
**Posts on this page:** 1\
**Showing post:** 7

<div class="post-metadata">

**Author:** ![Marloes](https://sea2.discourse-cdn.com/flex020/user_avatar/community.fibery.io/marloes/32/5926_2.png) [@Marloes](https://community.fibery.io/u/Marloes)\
**Post date:** [December 6, 2023, 7:17pm UTC](https://community.fibery.io/t/replace-regex-help/5499/7 "2023-12-06T19:17:58Z")

</div>

Ah, makes sence.

Well the ultimate objective is in line with [this topic](https://community.fibery.io/t/create-highover-context-based-on-lower-many-many-relations/5463). So indeed…

> [@Chr1sG](#):
>
> compare the IDs of the enities in two collection fields…?

Since there is no way to union two collection fields using a formule we have created a workaround like Yvette explained in the other post.

But we also need to be able to make corrections, when a lead isn’t interested in a product anymore. So to make it happen we

In our case I can’t see how an automation could update the [Instant - Product ID’s], because it is a join formula based on the linked product ID’s.

```auto
If(
  [Uitsluiten van 'Interesse in'] = true,
  "",
  If(
    [Interesse in product].Count() < 1,
    "",
    [Interesse in product].Join("[" + [Public Id] + "]", " ")
  )
)

```

Think we need to find a different solution (read workaround). 🥸🤣

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_[View the full topic](https://community.fibery.io/t/replace-regex-help/5499)._