From your question i cannot geta clear picture of your use case, so my answer may be completely off. Nevertheless: this is a way to show a list of selected companies on another page.
1. add a nonpersistable helper to your domainmodel to be able to temporarily store the list of selected companies. This may look somewhat like this:
2. Add a microflow action button on top of your datagrid. Connect it to a microflow whith a companylist as input parameter:
The create object activity looks like this:
3. Pass the companyHelper as page parameter to the sceond page.
4. In the second page, place eg a Gallry widget using a microflow as datasource.
The datasource microflow looks somewhat like this:
Does this come close to what you are looking for?
I hope this helps.